Laser Hair Removal

Introduction

Laser hair removal is one method of treatment for unwanted body hair. Up to 22% of women in North America have excessive or unwanted facial hair, which negatively affects the quality of life for many individuals.¹ Men also feel compelled to rid themselves of unwanted body hair, as dictated by popular culture and appearance anxieties. Body hair may be undesirable for patients for cultural, social, cosmetic, or psychological reasons; unwanted hair can result in feelings of embarrassment or emotional burden that may impede patients' relationships or daily activities. This level of impairment is comparable to that experienced by patients with psoriasis and eczema and eclipses that experienced by patients with acne.

Adequate methods for hair removal have long been in demand; long-term hair removal with minimal adverse effects is the ultimate goal. Laser hair removal has become well established as an effective form of treatment for unwanted body hair.

The shaving and hair removal market in the United States increased 8% between 2002 and 2007 and is currently 1.8 billion dollars annually.² None of the hair removal methods practiced today provides complete or permanent hair removal. This goal will likely be reached with a more complete understanding of anatomy, physiology, hair growth cycles, and laser-tissue interactions, and as more sophisticated technologies emerge.

For news, CME, and expert viewpoints on aesthetic procedures, visit Medscape’s Aesthetic Medicine Resource Center.

History of the Procedure

Numerous methods are successful in temporarily removing hair.^1,3

• Manual plucking
  • This method is an easy and practical way to remove single hairs and can be utilized by most individuals for clearing small numbers of unwanted hairs. The hair shaft must be long enough to be grasped by tweezers.
  • Plucking often induces a hair follicle into its active growth phase, or anagen, thus stimulating new hair growth. Additionally, it can create postinflammatory hyperpigmentation, true or pseudofolliculitis, and, very rarely, scarring.
• Shaving
  • Although fast and effective for clearing a large surface area of hair, shaving is the most temporary method of hair removal, as it only cuts the hair at the skin surface. As the hair continues to grow, the blunt end of the cut hair is more noticeable because it is thicker than a normal tapered end.
  • Disadvantages include skin lacerations, potential pyoderma, folliculitis, ingrown hairs, and postinflammatory hyperpigmentation. Many women may not use this method on certain areas of the body because of masculine connotations of shaving the face and neck.
• Waxing or sugaring⁴
  • Application of a warmed wax or a sugary paste to areas of hair-bearing skin and then removing it, along with the unwanted hair, is a popular method of hair removal and is commonly performed at salons and spas. This method may be used over large skin surface areas (eg, legs, arms, back) or small controlled areas (eg, face, eyebrow, bikini area). New hair growth appears more slowly than with shaving, as the hair must grow to the level of the skin surface before it appears.
  • Stripping of the wax or sugar paste from the skin is often unpleasant or painful and may cause adverse effects such as irritant dermatitis, true or pseudofolliculitis, hyperpigmentation, scarring, and thermal burns from hot wax or poor technique.
• Depilatory preparations
  • Preparations containing thioglycolates or strontium sulfide are the most widely used chemical depilatories. These agents disrupt the disulfide bonds (especially cysteine) that hold hair cells together, thus dissolving the hair. Like shaving, this method offers only a brief hair-free period, as hair continues to grow from the level of the skin surface.
  • The major adverse effect is the potential for irritant or allergic contact dermatitis, which may cause significant itching or rash.
• Chemical bleaching
  • Bleaching with hydrogen peroxide is an effective method of disguising the presence of hair but does not actually remove hair.
  • This is particularly effective for individuals with fine but dark and, therefore, noticeable hair on the arms, face, or neck.
• Electrolytic therapy
  • Successful electrolysis can achieve permanent hair follicle destruction to some degree in 15-80% of patients. It employs a weak direct current that passes through a negative electrode (anode) inserted in the hair follicle and a positive electrode (cathode) in the form of a wet pad in the patient's hand. Follicular destruction is achieved via the formation of toxic sodium hydroxide (a free radical). Electrothermolysis uses an alternating current that causes direct thermal destruction of the hair follicle.
  • Each hair must be treated individually and the process is slow and may be painful. Adverse effects include pain, scarring and hypo- or hyperpigmentation.
• Medicated treatment with eflornithine
  • Available by prescription only, eflornithine 13.9% cream was approved for topical use by the Food and Drug Administration (FDA) on July 31, 2000. Topical eflornithine may irreversibly inhibit skin ornithine decarboxylase activity, resulting in a reduction in the rate of hair growth.¹ The onset of action may take 4-8 weeks of using the topical cream for unwanted facial hair on the mustache and chin area.
  • The most common adverse effects of topical eflornithine cream include, but are not limited to, acne, pseudofolliculitis barbae, skin irritation, and rash.
• Laser hair removal
  • Since 1996, when photoepilation-using laser technology first became available for use, numerous advances have occurred in laser hair removal, resulting in different types of lasers now available for treatment of excessive hair. Laser hair removal is based on the theory of selective photothermolysis, or selective destruction of the follicular unit, resulting in significant hair reduction in treated areas.
  • Adverse effects are primarily related to epidermal damage by partial absorption of laser energy by the surrounding skin. This effect has been more pronounced in darker-skinned individuals whose increased skin melanin concentration places them at a higher risk of adverse effects. These adverse effects include blistering, hypo- or hyperpigmentation, scabbing, or, very rarely, permanent scarring.

Etiology

Excessive hair growth in men or women may be classified into either hirsutism or hypertrichosis, depending upon the distribution on the body. (Click here to complete a Medscape CME activity on hirsutism.) Other disorders, such as pseudofolliculitis barbae or acne keloidalis nuchae, may be caused by the hair itself, causing ingrown hairs and localized inflammatory reactions that may result in pigmentary disorders, hair loss, and scarring.

Indications

Hirsutism

Hirsutism is defined as an excess of thicker darker hairs in a male pattern of distribution where they are normally thin or absent in the female. Affected areas are those that are stimulated by circulating androgens and include the face, chest, arms, and areolae. This disorder may be caused by several types of endocrine disorders that lead to excessively high androgen levels or by hair follicles that are particularly sensitive to normal levels of androgens. The latter accounts for approximately 95% of all reported cases. An estimated 1 in 20 women of reproductive age are affected by this disorder.

Treatment for excessive hair in hirsutism is not generally required if no clear etiology of the disorder exists and the patient does not find the excessive hair growth objectionable. However, treatment generally relies upon antiandrogen to inhibit the effects of androgens on the skin, such as 5-alpha-reductase inhibitors, spironolactone, or flutamide. Whether choosing to treat medically or with any of the aforementioned methods of hair removal, patients must understand that treatment is long-term and must be continued to maintain low levels of visible hair.

Hypertrichosis

A hair growth pattern in a nonandrogen-dependent pattern is termed hypertrichosis and may involve vellus, terminal, or lanugo type hair. This may be associated with a number of congenital syndromes or occur as an isolated finding. What is considered a normal amount and appearance of body hair can vary widely among different ethnic groups, and treatment should be tailored to the needs or desires of the individual patient. Hypertrichosis may be an unwanted adverse effect of medications such as cyclosporine, minoxidil, and oral and topical corticosteroids that are used to treat other disorders.

Pseudofolliculitis barbae

When hair grows in a curly and tightly coiled pattern, patients may be afflicted with numerous ingrown hairs that may cause skin irritation, papules, and pustules. These may eventually lead to changes in pigmentation and even scarring. Pseudofolliculitis barbae occurs most commonly in the underarm or bikini area with shaving, or, in men, at the lower neck, where coarse facial hair grows. Laser hair removal is effective in treating this disorder by temporarily or permanently removing the hair from the chronically inflamed lesion. Laser treatment leads to resolution and healing of the papular and pustular lesions, dramatically improving skin texture and the associated postinflammatory hyperpigmentation.

Acne keloidalis nuchae

Acne keloidalis nuchae is most commonly seen in African Americans and is characterized by follicular papules and chronic plaques on the occipital area of the scalp. It may often lead to keloidal thickening of the skin and permanent scarring. In early lesions, an entrapped hair is usually in evidence, and early treatment with laser hair removal is most effective at this stage. The entrapped hair acts as a foreign body in the skin and, when chronic, can cause skin changes, decreased hair growth, and scarring of the affected area. The treatment goals with laser hair removal for this disorder are to destroy the impacted hair and cause a delay in new hair growth, thus decreasing further scarring.

Relevant Anatomy

In order to gain a more comprehensive understanding of how laser hair removal procedures work, one must have knowledge of relevant hair microanatomy, physiology, and growth cycles associated with growth of hair on the body.

Hair follicles are found over almost the entire body surface, with the exceptions of the palms of the hands and soles of the feet. Each person has approximately 5 million individual hair follicles. Hair follicles may be straight, wavy, helical, or spiral, and the morphologic features of follicles vary among different anatomic locations and racial backgrounds. White persons typically have thinner hair shafts than persons of Asian or African American backgrounds. The density of hair follicles in a given skin surface area also varies widely among individuals. Hair shape is also highly variable; on cross-section, straight hair tends to be round and wavy or spiral hair is oval. Keep in mind the variations in color, texture, and amount of hair on a given body surface area when deciding upon the need for hair removal procedures.

Types of hair

Adult hair has 2 primary types. Vellus hair can be found over the entire body and appears as soft, fine, short hairs that are nonpigmented or very lightly pigmented and can be all but invisible. Terminal hair is the longer, coarser, and more darkly pigmented hair found on the scalp, underarm area, and groin. Subgroups of terminal hair include those on the scalp, pubic region, and eyebrows. Terminal hair is also found on the androgen-sensitive areas of the body, such as the beard and chest area in males. Although greatly outnumbered by vellus hairs, terminal hairs are more important, as they are responsible for the appearance of hair on the body. They may aid in enhancing a person's image, or they can cause great anguish and distress due to their distribution, length, or texture.

Hair follicle anatomy

Hair follicles are associated with other structures within the skin. As the hair follicles develop, they become associated with developing sebaceous glands, apocrine glands, and erector pili muscles. Together, these structures form the folliculosebaceous-apocrine unit.

Each hair follicle may be divided into 4 histologic divisions, which are (from superficial to deep) the infundibulum, isthmus, stem, and bulb.

• The infundibulum is the most distal portion of the hair in the follicle, extending from the surface of the skin down to the entrance of the apocrine gland into the follicle.
• The isthmus of the hair then extends from the apocrine gland entrance to the connection to the sebaceous gland.
• Still deeper, the stem extends from the sebaceous gland opening to the erector pili muscle attachment. The action of this muscle makes the hair stand erect, causing goose bumps.
• The bulb of the hair follicle is deep to the attachment of the erector pili muscle and is the site of the follicular matrix. This is the principal site responsible for hair growth and development.

Hair phases

Adult hair has 3 distinct phases of development: anagen, catagen, and telogen. As hairs progress through these phases, they are affected differently by treatment with laser-assisted hair removal.

• Anagen is the phase in which active hair growth occurs. Follicular matrix cells are actively producing cells that will make up the growing hair. The growing hair consists of all 4 histologic divisions in anagen.
• In catagen (the regression phase), matrix cells degenerate and the bulb begins to atrophy, causing the hair follicle to shrink.
• Telogen is the final resting phase of the hair follicle. Growth of the hair has stopped, and the follicle becomes inactive. Now the follicle contains only the superficial components, the infundibulum and the isthmus. During telogen, the hair is released from its attachment to the skin and sloughs away. The process begins again in anagen to form a new hair.

The length of time spent in each phase depends upon the location of the hair. On the scalp, hair follicles spend up to 10 years in anagen, but on the trunk, brow, and limbs, anagen lasts no longer than 6 months. Catagen lasts only 2-3 weeks, and telogen lasts from 3-4 months.

Up to 90% of hairs in a given body location can be in the anagen phase at a given time. This fact becomes important because only hairs in the anagen phase of development are susceptible to injury during a session of laser-assisted hair removal. Thus, multiple treatments are necessary to treat all hair follicles on a given body surface area.

Melanin

Melanin is a biologic pigment that is found in many cells in the body and is primarily responsible for the color of the skin and hair. The primary function of melanin in the skin is to protect it from the harmful effects of sunlight. The amount of melanin in hair and skin varies widely between individuals and races and is determined by the concentration of melanin within the skin. This variability produces a great range of hair darkness, skin color, and tone.

Melanin is the target chromophore, or light-absorbing molecule, for laser treatment and has an absorption spectrum of 250–1200 nm, which spans the entire ultraviolet, visible, and infrared light ranges. Melanin absorbs energy in the form of heat from a pulse of laser light. This heat causes thermal injury to the melanin-containing cell and its surroundings. Ideally, the laser energy is absorbed selectively by the melanocytic hair bulb and matrix, thus destroying the hair follicle and its capacity to regrow, while protecting the surrounding tissue where the melanin concentration is minimal. In persons with darker skin, however, the higher levels of melanin in heavily pigmented skin compete as a chromophore for the laser light. This light is converted to heat and can cause skin blistering or changes in skin pigmentation.

Contraindications

• Patients with hirsutism may actually have a more serious underlying endocrine disorder. Causes of hirsutism should be avidly sought and treated, if necessary.
• For patients with chronic or active herpes simplex virus infections, pretreatment with antiviral medications can be initiated, especially when lesions appear in the body area to be treated. Antiviral treatment typically begins 1 day prior to laser treatment and continues for a total of 5-7 days.
• Patients with a history of hypertrophic scarring or keloid formation should be treated judiciously because of possible problems in healing if skin damage is sustained.
• Patients taking isotretinoin (Accutane) should stop the medication for 6 months prior to laser hair removal treatment because of skin sensitivity. This issue has been addressed but has not yet been proven in a clinical trial.
• Laser hair removal may be contraindicated in patients taking photosensitizing drugs activated by ultraviolet A wavelengths. Lasers operating in the visible to infrared spectrum are generally thought to be safe for use with patients taking these medications.
• Patients with tattoos on the body surface areas selected for laser hair removal should be instructed that the appearance of the tattoo might be affected by the use of laser devices. Treatment may lighten or darken certain pigments of the tattoo.
• Effective hair removal with laser-assisted devices requires the presence of a hair follicle for photothermolysis to commence. Prior history of recent waxing, plucking, sugaring, electrolysis, or other methods of complete hair removal should be ascertained.

Benefits of Exercise

Longevity and Aging

Exercise, even after age 50, can add healthy and active years to one's life. Studies continue to show that it is never too late to start exercising and that even small improvements in physical fitness can significantly lower the risk of death. Simply walking regularly can prolong life in the elderly. Moderately fit people, even if they smoke or have high blood pressure, have a lower mortality rate than the least fit. Resistance training is important for the elderly, because it is the only form of exercise that can slow and even reverse the decline in muscle mass, bone density, and strength. Adding workouts that focus on speed and agility may be even more protective for older people. Flexibility exercises help reduce the stiffness and loss of balance that accompanies aging.

Cardiovascular Health (Heart Disease and Stroke)

General Guidelines. Inactivity is one of the four major risk factors for heart disease, on par with smoking, unhealthy cholesterol, and even high blood pressure. Like all muscles, the heart becomes stronger and larger as a result of exercise so it can pump more blood through the body with every beat. Exercise does not increase the maximum heart rate, but a fit heart can pump more blood at this maximum level and can sustain it longer with less strain. The resting heart rate of those who exercise is also slower, because less effort is needed to pump blood. For preventing heart disease frequency of exercises may be more important than duration. Exercise even helps reverse some of the effects of smoking. Children should be especially encouraged to exercise every day to prevent heart disease later in life.

Effect on Coronary Artery Disease and Cholesterol Levels. People who maintain an active lifestyle have a 45% lower risk of developing coronary heart disease than do sedentary people. A recent study reported that moderate dietary changes improve cholesterol levels and so lower the risk for coronary artery disease only when an aerobic exercise program is also followed. Regular aerobic exercises -- brisk walking, jogging, swimming, biking, aerobic dance, and racquet sports -- are the best forms of exercise for lowering LDL and raising HDL cholesterol levels. It may take up to a year of sustained exercise for HDL levels to show significant improvement. Burning at least 250 calories a day (the equivalent of about 45 minutes of brisk walking or 25 minutes of jogging) seems to confer the greatest protection against coronary artery disease. Even moderate exercise, however, reduces the risk of heart attack, but in terms of raising HDL levels, more is better. Resistance (weight) training offers a complementary benefit by reducing LDL levels. Triglycerides, which rise after a high-fat meal, can be lowered either with a single, prolonged (about 90 minutes) aerobic session or by several shorter sessions during the day. One study indicates, however, that short-bursts of exercise actually increase LDL oxidation -- the process that makes LDL dangerous to the heart -- so individuals should always aim for a consistency in their exercise program. Before engaging in any strenuous exercise, it is advisable to consult a physician.

High Blood Pressure. Studies indicate that regular exercise helps keep arteries elastic, even in older people, which in turn keeps blood flowing and blood pressure low. Sedentary people have a 35% greater risk of developing hypertension than athletes do. No person with high blood pressure should start an exercise program without consulting a physician. Studies have shown that high-intensity exercise may not lower blood pressure as effectively as moderate intensity exercise. In one study, for example, moderate exercise (jogging two miles a day) controlled hypertension so well that more than half the patients who had been taking drugs for high blood pressure were able to discontinue their medication. Studies have indicated that T'ai Chi, an ancient Chinese exercise involving slow, relaxing movements may lower blood pressure almost as well as moderate-intensity aerobic exercises. Before exercising, people with hypertension should avoid caffeinated beverages, which increase heart rate, the workload of the heart, and blood pressure during physical activity.

Stroke. The benefits of exercise on stroke are uncertain. According to one analysis, a group of 11,000 men, men who burned between 2,000 and 3,000 calories a week (about an hour of brisk walking five days a week) cut their risk of stroke in half. Groups who burned between 1,000 and 2,000 calories or more than 3,000 calories per week also gained some protection against stroke but to a lesser degree. In the same study, exercise that involved recreation was more protective than exercise routines consisting simply of walking or climbing.

Heart Failure. Traditionally, heart failure patients have been discouraged from exercising. Now, exercise is proving to be helpful for many of these patients and, when performed under medical supervision, does not pose a risk for a heart attack. In one study, patients between the ages of 61 and 91 increased their oxygen consumption by 20% after six months by engaging in supervised treadmill and stationary bicycle exercises. Performing daily hand grip exercises may improve blood flow through the arteries of patients with heart failure.

Diabetes

Diabetes, particularly type 2, is reaching epidemic proportions throughout the world as more and more cultures adopt Western dietary habits. Aerobic exercise is proving to have significant and particular benefits for people with both type 1 and type 2 diabetes; it increases sensitivity to insulin, lowers blood pressure, improves cholesterol levels, and decreases body fat. Regular exercise, even of moderate intensity, improves insulin sensitivity. In fact, studies of older people who engage in regular, moderate, aerobic exercise (e.g., brisk walking, biking) lower their risk for diabetes even if they don't lose weight. Anyone on insulin or who has complications from diabetes must take special precautions before embarking on a workout program (see, What Are the Hazards of Exercise?, below).

Effects on Bones and Joints

Osteoarthritis. Exercise helps to reduce pain and stiffness, and increases flexibility, muscle strength, endurance, and well being. Exercising also helps people reduce their weight and maintain weight loss. Osteoarthritis patients should avoid high-impact sports such as jogging, tennis, and racquetball. The three types of exercise that are best for people with arthritis are range of motion, strengthening (or resistance), and aerobic exercises. Strengthening exercises include isometric exercises (pushing or pulling against static resistance) and stretching exercises to build strength and flexibility without unduly stressing the joints. These exercises may be particularly important if leg muscle weakness turns out to be a cause of osteoarthritis, as some research suggests. Low-impact aerobics also help stabilize and support the joints and may even reduce inflammation in some joints. Cycling and walking are beneficial, and swimming or exercising in water is highly recommended for people with arthritis.
One study compared a group of patients who embarked on an aerobic and resistance exercise program with a group that received patient education; the exercising group developed less disability and pain and showed a better ability to perform physical tasks. Patients should strive for short but frequent exercise sessions guided by physical therapists or certified instructors.

Osteoporosis. Exercise is very important for slowing the progression of osteoporosis. Women should begin exercising before adolescence, since bone mass increases during puberty and reaches its peak between ages 20 and 30. Weight bearing exercise, which applies tension to muscle and bone, encourages the body to compensate for the added stress by increasing bone density by as much as 2% to 8% a year. High-impact weight-bearing exercises, such as step aerobics, are very protective for premenopausal women. These exercises, however, increase the risk for osteoporotic fractures in elderly patients, who would benefit most from regular, brisk, long walks. Even moderate exercise (as little as an hour a week) helps reduce the risk for fracture, but everyone who is in good health should aim for more. Careful weight training is beneficial as well for older women. Low-impact exercises that improve balance and strength, particularly yoga and T'ai Chi, have been found to decrease the risk of falling; in one study, T'ai Chi reduced the risk by almost half.

Back Problems. One of the most common complaints of modern men and women, lower-back pain, afflicts up to 80% of all Americans. Sedentary living, obesity, poor posture, badly designed furniture, and stress all contribute to back pain. An appropriate exercise program focusing on flexibility and strengthening the muscles in the abdomen may help prevent back problems. Yoga stretching is beneficial and can be incorporated into the warm-up and cool-down periods. The best exercises for athletes with bad backs include swimming, walking, and cross-country skiing. High-impact sports, including aerobic dance and downhill skiing, should be avoided. Exercises that strengthen the abdominal muscles such as partial sit-ups, which maintain the back's normal curve and help support the body's weight, can alleviate stress on the lower back. However, the classic full sit-up (raising your head and shoulders off the floor up to your knees) may aggravate back pain and should be avoided by anyone at risk for lower back problems.

Lung Disease

Although exercise does not improve lung function (except for intense, regular aerobic exercise), training helps some patients with chronic lung disease by strengthening their limb muscles, thus improving endurance and reducing breathlessness.

Cancer

A number of studies have indicated that regular, even moderate, exercise reduces the risk of colon cancer. Strenuous activity, in fact, adds only slight or no additional benefit. Moderate exercise may also help reduce the risk for prostate cancer and possibly for breast cancer. A recent study of 100,000 nurses, however, suggested that the benefits of exercise on breast health may be greater or lesser at different times in a woman's life, depending on her menstrual status and estrogen levels. For example, the study found no added protection against from exercise in young adulthood (when the disease is uncommon in any case).

Effects on Colds and Flu

Although offering no evidence of improved immunity from exercise, one study reported that people who exercised as little as once a week in employee fitness programs averaged nearly five fewer sick days annually than those who did not participate in such programs. The immediate effect of exercise on the immune system is uncertain. High-intensity or endurance exercises might actually suppress the immune system while they are performed. Some highly trained athletes, for instance, report being susceptible to colds after strenuous events. A recent study suggested that in people who already have colds, exercise has no effect on the illness -- severity or duration of the infection. People should avoid strenuous physical activity when they have high fevers or widespread viral illnesses, however.

Central Nervous System Diseases

People with multiple sclerosis, Parkinson's disease, and Alzheimer's disease should be encouraged to exercise. Specialized exercise programs that improve mobility are particularly valuable for Parkinson's patients. Patients with neurological disorders who exercise experience less spasticity as well as reduction in -- and even reversal of -- muscle atrophy. In addition, the psychological benefits of exercise are extremely important in managing these disorders. Exercise machines, aquatic exercises, and walking are particularly useful.

Pregnancy

Healthy women with normal pregnancies should exercise at least three times a week, being careful to warm up, cool down, and drink plenty of liquids. Many prenatal calisthenics programs are available. Experts advise, in general, that when exercising, the expectant mother's pulse rate should not exceed 70% to 75% of the maximum heart rate or more than 150 beats per minute. Fit women who have exercised regularly before pregnancy, however, may work out more intensively as long as no discomfort occurs.
According to a new study, vigorous exercise may improve the chances for a timely delivery. Overly strenuous exercise during pregnancy is not advocated, however, for women who did not exercise intensely before becoming pregnant. And all pregnant women should avoid high-impact, jerky, and jarring exercises, such as aerobic dancing, which can weaken the pelvic floor muscles that support the uterus. During exercise, women should monitor their temperature to avoid overheating -- a side effect that can damage the fetus. (No pregnant women should use hot tubs or steam baths, which can cause fetal damage and miscarriage.)
Swimming may be the best option for most pregnant women. It involves no impact, overheating is unlikely, and swimming face down promotes optimum blood flow to the uterus. Walking is also highly beneficial. To strengthen pelvic muscles, women should perform Kegel exercises at least 6 times a day, which involve contracting the muscles around the vagina and urethra for 3 seconds 12 to 15 times in a row.

Gastrointestinal Problems

Older people who exercise moderately may have a lower risk for severe gastrointestinal bleeding. Experts suggest that moderate exercise might even reduce the risk for some intestinal disorders, including ulcers, irritable bowel syndrome, indigestion, and diverticulosis.

Leg Cramps

Exercise can even improve pain from clogged arteries in the legs, a condition called intermittent claudication. The best approach in such cases is to walk until pain develops; then rest until pain resolves before resuming walking. In six-month studies, people had tripled the amount of time they could walk before the onset of pain.

Weight Loss

Exercise burns calories and can help individuals fight obesity. If caloric intake remains constant, regular workouts lead to weight loss. Be forewarned, however, that the pounds won't melt off magically. It takes 35 miles of walking or jogging to consume the calories in one pound of fat. Effective weight loss means a long-term commitment to a regular program of vigorous exercise. One recent study indicated that for obese patients, a few daily sessions for as short as 10 minutes each was effective in helping the patients adhere to an exercise program. Abdominal crunches may help replace abdominal fat with muscle. To perform this exercise, the individual lies on the back with the head and shoulders raised; he or she contracts the stomach muscles, curling the torso slightly forward. Abdominal fat is a particular danger to the heart, although it is unknown whether doing crunches will specifically protect against heart disease. Swimming is less effective than walking or cycling in reducing body fat, but overall regular aerobic exercise is a good way to shed pounds. Contrary to popular belief, exercise does not increase appetite in people who want to lose weight; oddly enough, however, exercise improves appetite in people who are already lean.
People should be warned that without dieting, weight loss may be minimal with exercise alone, because dense muscle mass replaces fat as the body gets more fit. Nonetheless, a fit body will look more toned and be healthier.

Psychological and Emotional Benefits

Aerobic exercise is linked with improved mental vigor, including reaction time, acuity, and math skills. Exercising may even enhance creativity and imagination. According to one study, older people who are physically fit respond to mental challenges just as quickly as unfit young adults. (Stretching and weight training appear to have no such effects.) Both aerobic and nonaerobic workouts have been shown to reduce depression. According to one study, exercise was as effective for improving mood in people with clinical depression as some common forms of psychotherapy. Either brief periods of intense training or prolonged aerobic workouts can raise levels of important chemicals in the brain, such as endorphins, adrenaline, serotonin, and dopamine, that produce feelings of pleasure, causing the so-called runner's high. One study found that teenagers who were active in sports have a much better sense of well being than their sedentary peers; the more vigorously they exercised, the better was their emotional health. In one study, regular brisk walking cut in half the incidence of sleep disturbances in people who suffer from them. It should be noted that exercise in the evening, however, can cause sleep disturbances. Rhythmic aerobic and yoga exercises may be particularly helpful for combating stress, anxiety, and sleeplessness.

How Hard to Exercise

How Hard Do I Need to Exercise to Burn Fat?

To answer this question we need to focus on two areas of the FIT principle (Frequency, Intensity, and Time of exercise). These two areas are intensity and time.

Let's look at 2 sample workouts performed by the same individual exercising on a stairclimber.

	SESSION #1	SESSION #2
Percentage of MHR	85%	65%
Exercise time	30 minutes	30 minutes
Calories expended during exercise	480	300
Percentage of calories from fat	50%	80%
Fat calories utilized	240	240

These numbers are used for the sole purpose of demonstrating how a higher intensity cardiovascular workout can achieve an equal or greater number of fat calories utilized as a lower intensity workout. Individuals caloric numbers will vary.

So you can work out at a higher intensity and still burn an equal or greater number of fat calories as compared to a lower intensity workout. The following are added benefits of the higher intensity workout.

Larger number of total calories utilized Metabolism remains elevated for a longer period of the time after exercise. You gain a higher level of cardiovascular conditioning. Keep in mind that individuals who are ill or injured should start at a lower intensity level until they have regained their health. Should Burning Fat Calories Be My Goal? I think not. I believe that caloric expenditure should be our main goal in exercise when we are trying to lose fat weight. The reason is that 3,500 calories equals one pound of fat. Theoretically if we ate an extra 3,500 calories in a week, we would gain a pound. The same applies to eating 3,500 fewer calories than our body needs in a week - we would lose a pound. Instead of eating 3,500 fewer calories and depriving our bodies of the fiber and nutrients that we need, let's eat nutritionally dense food, make healthy food choices, and expend those calories in the form of exercise. Whether the majority of calories expended are from fat or glycogen, ultimately calories are calories when it comes to exercise. While keeping in mind that you don't want to exercise at such a high level that you can only last a few minutes, remember that the longer you exercise the more calories you expend, and the higher your intensity, the more calories you expend. If you are in good physical condition and you're trying to lose or maintain weight, and you feel like exercising at a higher heart rate, go ahead.

New Genes Implicated In High Blood Pressure

Researchers at the Johns Hopkins University School of Medicine, along with an international team of collaborators, have identified common genetic changes associated with blood pressure and hypertension. The study, reporting online in Nature Genetics, breaks new ground in understanding blood pressure regulation and may lead to advances in hypertension therapy. "Strikingly, none of the genes we identified as having common variation are part of the system we know about that regulates blood pressure - the genes identified are not the ones targeted by current prescription drugs to control hypertension," says Aravinda Chakravarti, Ph.D., head of the Center for Complex Disease Genomics in the McKusick-Nathans Institute of Genetic Medicine at Hopkins. "If we can increase the number of genes implicated in blood pressure maintenance from the current 12 to the expected 50 in the next year, our understanding of the biology will change completely." Consistently elevated blood pressure increases the risk of stroke, heart attack and kidney failure, among other conditions. High blood pressure affects about 30 percent or more of adults and causes millions of deaths worldwide each year. While the environment (diet, physical activity, stress, etc.) affects blood pressure, genetics also plays a substantial role and, according to Chakravarti, may increase some people's risk of developing high blood pressure under specific environmental exposures; however, many genes involved in blood pressure regulation remain unknown. To identify genes involved in blood pressure maintenance and hypertension, the researchers analyzed differences in the genomes of nearly 30,000 people of European descent whose average systolic blood pressures ranged from 118 mm Hg to 143 mm Hg and average diastolic blood pressures ranged from 72 mm Hg to 83 mm Hg. These individuals were part of a long-term study of cardiovascular health and disease supported by the National Institutes of Health called ARIC (Atherosclerosis Risk in Communities). The researchers looked for genetic differences that correlated with high blood pressure and found 11 variations or changes in DNA sequence that appear to regulate blood pressure levels. Changes in one gene, ATP2B1, were linked to both blood pressure and hypertension. The gene ATP2B1 makes a protein that pumps calcium out of the cells that line the interior of blood vessels. Changes in SH2B3, a protein involved in the immune response, were also linked to increased blood pressure. Researchers also identified changes in genes involved in cell growth as well as genes necessary for correct heart development. Identifying genes in unexpected pathways emphasizes the many levels of precise blood pressure regulation, says Chakravarti. According to Chakravarti, each of the genetic differences found is common in the population and causes only small changes in blood pressure. This study, he says, supports the idea that changes in many genes contribute to high blood pressure and hypertension. Chakravarti believes the combination of multiple changes in different genes may increase blood pressure significantly although the affect of each individual change on blood pressure is small. "Hypertension is difficult to study; it is a trait, not a disease per se unless left untreated, and many things contribute to it," says Chakravarti. "These findings identify more pathways important for blood pressure maintenance and may lead to improvements in hypertension therapy and the formation of early detection systems." Authors on the paper are Daniel Levy, Andrew D. Johnson, Ramachandran S. Vasan, Shih-Jen Hwang, Santhi K. Ganesh, Christopher J. O'Donnell, Emelia J. Benjamin, Caroline S. Fox, Thomas J. Wang and Martin G. Larson of the National Heart, Lung, and Blood Institute; Kenneth Rice, Nicole L. Glazer, Thomas Lumley, Joshua Bis and Bruce M. Psaty of University of Washington; Germaine C. Verwoert, Abbas Dehghan, Yurii Aulchenko, Fernando Rivadeneira, Francesco U.S. Mattace-Raso, Eric J.G. Sijbrands, Albert Hofman, André G. Uitterlinden, Jacqueline C.M. Witteman and Cornelia M. van Duijn of Erasmus Medical Center; Lenore J. Launer and Tamara B. Harris of the National Institute of Aging; Alanna C. Morrison and Eric Boerwinkle of University of Texas Health Science Center; Thor Aspelund, Gudny Eiriksdottir, Albert V. Smith and Vilmundur Gudnason of the Icelandic Heart Association; Xiuqing Guo, Kent Taylor and Jerome I. Rotter of Cedars-Sinai Medical Center; Gary F. Mitchell of Cardiovascular Engineering Inc.; Gerardo Heiss of Carolina Cardiovascular Biology; and Georg B. Ehret, Anna Köttgen, Dan E. Arking, Robert B. Scharpf, Josef Coresh and Aravinda Chakravarti of the Johns Hopkins University School of Medicine

Genetic Clues To Blood Pressure

An international research team has identified a number of unsuspected genetic variants associated with systolic blood pressure (SBP), diastolic blood pressure (DBP), and hypertension (high blood pressure), suggesting potential avenues of investigation for the prevention or treatment of hypertension. The research was funded in part by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health and by several other NIH institutes and centers. The analysis of over 29,000 participants is being presented at the American Society of Hypertension, Inc. scientific meeting on May 8, 2009, and is published online in the journal Nature Genetics on May 10, 2009. "This study provides important new insights into the biology of blood pressure regulation and, with continued research, may lead to the development of novel therapeutic approaches to combat hypertension and its complications," said NHLBI Director Elizabeth G. Nabel, M.D. About 1 in 3 adults (approximately 72 million people) in the United States has high blood pressure. Hypertension can lead to coronary heart disease, heart failure, stroke, kidney failure, and other health problems, and causes over 7 million deaths worldwide each year. Blood pressure has a substantial genetic component and hypertension runs in families. Previous attempts to identify genes associated with blood pressure, however, have met with limited success. In a genome-wide association study (GWAS), researchers scanned millions of common genetic variants of individuals from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium to find variants associated with blood pressure and hypertension. This extensive resource includes white men and women from the Framingham Heart Study, Atherosclerosis Risk in Communities study, Cardiovascular Health Study, the Rotterdam Study, the Rotterdam Extension Study, and the Age, Gene/Environment Susceptibility Reykjavik Study. The investigators identified a number of genetic variants or single-nucleotide polymorphisms (SNPs) associated with SBP, DBP, and hypertension. When they jointly analyzed their findings with those from the GWAS of over 34,000 participants in the Global BPgen Consortium (whose results are presented in an accompanying paper in the same issue of Nature Genetics), they identified 11 genes showing significant associations across the genome: four for SBP, six for DBP, and one for hypertension. "Large scale genome-wide association studies are providing a number of important insights into identifying genes that play a role in diseases with major public health impact," said Dr. Daniel Levy, first author of the study and director, the NHLBI's Framingham Heart Study and Center for Population Studies. "We have identified eight key genes, few of which would have been on anyone's short list of suspected blood pressure genes until now." The international research team included Cornelia M. van Duijn, Ph.D., Erasmus Medical Center, Rotterdam, the Netherlands; Aravinda Chakravarti, Ph.D., Johns Hopkins University; Bruce Psaty, M.D., Ph.D., University of Washington; and Vilmundur Gudnason, M.D., Ph.D., Icelandic Heart Association, Kopayogur, Iceland. The blood pressure genes include ATP2B1 which encodes PMCA1, a cell membrane enzyme that is involved in calcium transport; CACNB2, which encodes part of a calcium channel protein; and CYP17A1 which encodes an enzyme that is necessary for steroid production. One detected variant is within the gene SH2B3 and has been associated with autoimmune diseases, hinting that pathways involved with the immune response may influence blood pressure. Blood pressure is measured in millimeters of mercury (mm Hg), and expressed with two numbers, for example, 120/80 mm Hg. The first number (systolic pressure) is the pressure when the heart beats while pumping blood. The second number (diastolic pressure) is the pressure in large arteries when the heart is at rest between beats. Researchers found that the top 10 gene variants, or SNPs, for systolic and diastolic blood pressure were each associated with around a 1 and 0.5 mm Hg increase in systolic and diastolic blood pressure, respectively. The prevalence of hypertension increased as the number of variants increased. People who carry very few blood pressure genetic risk variants have blood pressure levels that are several mm Hg lower than those who carry multiple risk variants. In practical terms this is enough to increase the risk for cardiovascular disease. A prolonged increase in DBP of only 5 mm Hg is associated with a 34 percent increase in risk for stroke and a 21 percent increase of coronary heart disease.