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The 25 Most Significant Health Benefits of Physical Activity and Exercise
Len Kravitz, Ph.D.

People of all ages can improve the quality of their lives and reduce the risks of developing coronary heart disease, hypertension, some cancers, and type 2 diabetes with ongoing participation in moderate physical activity and exercise. Daily exercise will also enhance one’s mental well-being and promote healthy musculoskeletal function throughout life. Although habitual physical activity is an attainable goal to a healthier life, only 48% percent of all American adults currently get 30 minutes of moderate intensity exercise per day on at least 5 days/week (CDC, 2005). A formidable challenge facing many personal trainers and health and fitness professionals is finding new approaches to motivate people to improve their well-being with consistent participation in physical activity and exercise. In fact, significant health benefits can be obtained by including moderate amounts of physical activity accumulated on most, preferably all days of the week. Fitness programs involving progressively increasing intensities of exercise will elicit even greater cardioprotective benefits (Swain and Franklin, 2006). There is a growing understanding of how levels of physical activity may positively effect cardiovascular, musculoskeletal, respiratory, endocrine function, and mental health. This article will bring to realization the evidence on 25 significant benefits linking physical activity to health enhancement. Some health benefits have been grouped together because of their physiological or metabolic associations.

1) Cardiovascular disease
The leading health-related cause of mortality for men and women in the U.S is cardiovascular disease (CVD). Meaningful cardiovascular health benefits may be attained with the long-term participation in cardiovascular exercise. To properly address the question of “how much exercise is enough,” the American College of Sports Medicine has recognized the need for physical activity and exercise, and updated its position stand on the recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults (ACSM, 2006) {see Side Bar 1}. Higher levels of cardiovascular fitness are associated with a 50% reduction in risk of CVD in men (Myers et al., 2004). Myers and colleagues demonstrated that increasing physical activity to 1000 kilocalories per week is associated with a 20% reduction of mortality in men. Hu and colleagues (2004) showed that physically inactive (engaging in less than 1 hour of exercise per week) middle-aged women doubled their risk of mortality of CVD as compared to their physically active female counterparts. It should be emphasized that Haskell (2003) notes that CVD is a multifactor process and that “not smoking, being physically active, eating a heart healthy diet, staying reasonably lean, and avoiding stress and depression are the major components of an effective CVD prevention program.”

2-4) Diabetes, Insulin Sensitivity and Glucose Metabolism
Diabetes has reached endemic proportions, affecting 170 million individuals worldwide (Stumvoll, Goldstein and van Haeften, 2005). One misfortunate health consequence of physical inactivity is the weakening of the body’s insulin regulatory mechanisms. Elevated insulin and blood glucose levels are characteristic features involved in the development of non-insulin-dependent diabetes mellitus. When insulin function starts breaking down there is a rise in the body’s blood sugar levels, with the eventual onset of ‘pre-diabetes’ and then type 2 diabetes. Diabetes is a growing disease in youth and adults, largely as a result of obesity and inactivity. Regular aerobic exercise meaningfully increases insulin sensitivity and glucose metabolism, which means the body’s cells can more efficiently transport glucose into the cells of the liver, muscle and adipose tissue (Steyn et al., 2004). Improvements in glucose metabolism with strength training, independent of alterations in aerobic capacity or percent body fat, have also been shown (Pollock et al., 2001). Although the mechanisms for improvement are not fully understood, it appears that both resistance training and aerobic exercise offer a strong protective role in the prevention of non-insulin-dependent diabetes mellitus.

5) Hypertension
Hypertension is a major health problem. Elevated systolic and diastolic blood pressures are associated with a higher risk of developing coronary heart disease (CHD), congestive heart failure, stroke, and kidney failure. There is a one-fold increase in developing these diseases when blood pressure is 140/90 mmHg (Bouchard & Despres, 1995). It is necessary for the personal trainer and fitness professional to educate clients that reducing weight and lowering alcohol and salt intake in their diet may also help reduce elevated blood pressure in many cases. Moderate-intensity aerobic exercise (40%-50% of VO2max), performed three to five times per week for a 30 to 60 minute session appears to be effective in blood pressure reduction (when elevated). The evidence that higher intensity exercise is more or less effective in managing hypertension is, at present, inconsistent due to insufficient data. In a recent meta-analysis (a statistical technique that combines the results of several studies) of 54 clinical aerobic exercise intervention trials, findings (in hypertensive men and women) included a reduction in systolic blood pressure by an average of 3.84 mmHg and 2.58 mmHg for diastolic blood pressure (Whelton et al., 2002). Although routine aerobic exercise usually will not affect the blood pressure of normotensive individuals, habitual aerobic exercise may be protective against the increase in blood pressure commonly seen with increasing age (Fagard, 2001).

During resistance exercise, systolic and diastolic blood pressures may show steep increases, which indicates that caution should be observed with persons with known cardiovascular disease or risk factors. These increases in blood pressure are dependent on the intensity of the contraction, the length of time the contraction is held, and the amount of muscle mass involved in the contraction. More dynamic forms of resistance training, such as circuit training, that involve moderate resistance loads and high repetitions with short rests are safe and associated with reductions in blood pressure (Pollock et al., 2001). Although there is relatively little research on blood pressure and resistance exercise as compared to aerobic training/blood pressure studies, one recent meta-analysis in resistance exercise intervention trials found a decrease of 3.2 mmHg and 3.5 mmHg for systolic and diastolic blood pressure, respectively (Cornelissen and Fagard, 2005).

6-8) Blood Triglycerides, HDL-Cholesterol, and LDL-Cholesterol
The link between cholesterol and CHD has been fairly well established through long-term studies of individuals with high levels of blood cholesterol and the incidence of CHD. High-density lipoprotein cholesterol (HDL-C) {the good cholesterol} levels are inversely and independently associated with reduced risk of CHD (Neiman, 2003). It is well established that a sedentary lifestyle contributes significantly to the development of CHD and unfavorable elevation of blood fats and cholesterol levels; physical activity plays an important role in decreasing these health risks.

The exercise thresholds established from longitudinal and cross-sectional training studies indicate that 15 to 20 miles/week of jogging or brisk walking, which is equivalent to 1200 to 2200 kilocalories of energy expenditure, may decrease blood triglycerides by 5 to 38 mg/deciliter (Durstine et al., 2002). That same threshold of exercise (15 to 20 miles/week of jogging or brisk walking) has been shown to elevate HDL-C (a positive alteration) 2 to 8 mg/deciliter. Durstine and colleagues continue that exercise training studies rarely show a decrease in total cholesterol or LDL-C (the bad cholesterol) unless there is a loss of body weight or dietary fat is decreased (or both). The serum level of LDL-C has been shown to be significantly reduced among women (a decrease of 14.5+/-22.2 mg per deciliter) and men (a decrease of 20.0+/-17.3 mg/deciliter) randomly assigned to a diet-plus-exercise group, as compared with to a control group (women had a decrease of 2.5+/-16.6 mg/deciliter; men had a decrease of 4.6+/-21.1 mg/deciliter) (Stefanick et al., 1998).

Although some studies have shown favorable impact of resistance training on blood lipids, others have reported no change. It may be that the resistance programs that best modify blood lipid profiles incorporate larger muscle mass and multi-segment exercises with a high total volume (reps x sets x load) prescription. Additional research needs to be conducted which controls for body composition changes, day-to-day variations in lipoproteins, dietary factors, and possible other training adaptations, to provide a more credible summary of the effect of resistance training on blood lipids and lipoproteins.

9) Stroke
Physical activity exerts at positive effect in lessoning the risk of stroke in men and women. Moderate-to-high physically active individuals have a lower risk of stroke incidence as compared to those persons accumulating little exercise. Statistics show that those who are moderately active have a 20% lower risk of stroke while those who are highly active have a 27% lower risk of stroke (Sacco et al., 2006). Sacco and colleagues suggest that these levels of physical activity tend to lower blood pressure (if high), reduce body weight (if over fat), enhance vasodilation of blood vessels (widening of inside of blood vessels), improve glucose tolerance (how body breaks down glucose) and promote cardiovascular health. The implementation of progressive aerobic exercise (for cardiovascular health) and strength training (for mobility and balance) is recommended to reduce the risk of stroke or recurrent stroke (Sacco et al., 2006).

10-13) Colon, breast, lung and multiple myeloma cancer
Physical activity and exercise are correlated with a lower incidence of colon cancer and breast cancer in men and women, respectively. Lee (2003) reports that moderate-to-vigorous physical activity has a greater protective effect than lower intensities of physical activity. She notes that physically active men have a 30% to 40% reduction of relative risk to colon cancer as compared to their inactive counterparts. It seems that about 30-60 minutes of moderate-to-vigorous exercise per day is needed for this decreased risk, with higher levels of exercise showing even lowered risk. In addition, physically active women have a 20% to 40% reduction in relative risk of breast cancer as compared to their inactive counterparts. It also appears that the 30-60 minutes of moderate-to-vigorous exercise per day is needed to elicit this risk reduction in breast cancer for women. Although more research is needed, it appears that physically active individuals may also have a lower risk of lung cancer, although lung cancer is relatively uncommon in non-smokers (Lee, 2003).

Multiple myeloma cancer is more common in persons after the age of 50 yrs (Robert-McComb, 2007). Robert-McComb explains that with multiple myeloma there is genetic damage to plasma cells, transforming them into malignant or myeloma cells. Chronic fatigue is frequently reported and a distressing side effect of many cancers, including multiple myeloma. However, patients doing 3-5 days of walking for 15-30 minutes per session and light resistance exercise (2-3 times per week) have demonstrated an increased overall quality of life.

The research is clear that there is no association with the incidence of rectal cancer and exercise (Lee, 2003). The data is also somewhat inconsistent whether exercise can have a positive influence on lowering the risk of prostate cancer in men. Clearly, the present research on physical activity and cancer prevention indicates that exercise has a different association with various site-specific cancers.

14) Osteoporosis
Physical activities that stimulate bone growth need to include progressive overload, variation of load, and specificity of load. Specificity of load refers to exercises that directly place a load on a certain region of the skeleton. With osteoporosis, a degenerative disease characterized by a loss of bone mineral density resulting in a susceptibility to bone fractures and health problems, it appears resistance training and weight bearing aerobic exercise may provide the needed stimulus for bone formation (Kohrt et al., 2004). Progressive overload is necessary so the bone and associated connective tissue do not exceed the critical level that would place them at risk. Exercise programs to maintain and increase bone growth should be full-body in nature, including exercises such as squats and lunges, which direct the forces through the axial skeleton and allow for greater loads to be utilized. In addition, evidence does suggest that moderate weight-bearing activity, such as brisk walking done regularly, and for a long-term basis, is effective in averting age-related bone loss. Harder relative intensities of effort and greater volume of physical activity are more effective in increasing bone density. Kohrt and colleagues recommend doing weight-bearing endurance activities 3 to 5 times per week, and resistance exercise 2 to 3 times per seek for a total of 30 to 60 minutes per day to preserve bone health during adulthood.

15-16) Musculoskeletal Health and Sarcopenia
Muscle mass, strength, power and endurance are essential contributing factors for the improvement in musculoskeletal health and the enhancement of movement capabilities (Marcell, 2003). Although these components of musculoskeletal health show substantial decreases with age, it has been suggested that this is due largely to a decrease in physical activity, and not solely age.

Sarcopenia is the age-related loss of muscle mass and strength (Marcell, 2003). Marcell adds that the rate of muscle loss with age is relatively consistent, approximately 1-2% per year starting at age 50. He notes that there is a linear relationship with loss of muscle strength and loss of independence, contributing to falls, fractures and admissions into nursing homes. In addition, there is a decrease in metabolic rate and maximal oxygen consumption (due to the loss of muscle mass).

Improved musculoskeletal health may allow elderly persons to more effectively perform activities of daily living and with less effort (ACSM, 2006). The 2006 ACSM Resistance Training Guidelines for elderly persons suggest performing at least one set of 8 to 10 exercises that use all of the major muscle groups. Each set should include 10 to 15 repetitions that elicit a somewhat hard intensity for the active older exerciser. For sarcopenia prevention, the selection of multi-joint exercises on machines is recommended, because this requires less skill, and may allow the user to more easily control the exercise range of motion.

17-18) Body Composition and Obesity
Obesity has risen to epidemic levels in the U.S., with over 65% of the U.S adults being overweight and 31% obese (ACSM, 2006). According to the Centers for Disease Control (CDC, 2007), overweight and obesity are associated with increased risk for hypertension, osteoarthritis, abnormal cholesterol and triglyceride levels, type 2 diabetes, coronary heart disease, stroke, gallbladder disease, sleep apnea, respiratory problems and some cancers (endometrial, breast, and colon).

The most favorable approach to weight loss is one that includes committed endurance exercise, resistance exercise, and caloric restriction within a sound behavioral modification delivery program. Weight loss achievements are most effective with increasing cardiovascular exercise up to 200 to 300 accumulated minutes of moderate-intensity (somewhat hard) exercise throughout 5 to 7 days per week (which is equivalent to expending 2,000 kilocalories per week exercising) (ACSM, 2006).

Resistance training and circuit training research has shown meaningful changes in body composition (Marx et al., 2001). Thus, one of the noteworthy benefits of resistance exercise, as it relates to body composition, is the positive impact of maintaining, or increasing fat-free body mass while encouraging the loss of fat body weight in a progressive overload resistance training program.

19) Arthritis
Arthritis is a broad term referring to greater than 100 rheumatic diseases. Of the many types of arthritis, osteoarthritis (a degenerative joint disease) and rheumatoid arthritis (an inflammatory disorder affecting multiple joints) are the two most prevalent (Maes and Kravitz, 2004). Arthritis is a health problem commonly characterized by stiffness, pain, and loss of joint function that affects people of all ages, genders and ethnic groups. It may imperil the physical, psychological, social and economic well-being of individuals, depriving them of their lifestyle independence. Physicians commonly prescribe exercise as a modality for the treatment of arthritis. Consistent exercise improves aerobic capacity, muscle strength, joint mobility, functional ability, and mood, without apparent increases in joint symptoms or disease (Finckh, Iversen and Liang, 2003). Exercise has been proposed to have a pain-relieving effect similar to that of a pharmacological treatment for some people. However, Finckh and colleagues suggest guarded caution in the exercise design of patients who have significant joint damage, especially in their weight-bearing joints. The authors continue that high-impact exercise is contraindicated in many cases of arthritis and should be replaced with swimming, aquatic exercise, aquatic walking, and biking, which are much safer on the weight bearing joints. Exercise programming for clients with arthritis should focus on gradually increasing cardiovascular conditioning, progressively overloading resistance exercise, increased flexibility, and steadily increasing flexibility and joint stability (Maes and Kravitz, 2004).

20) Stress
A growing body of research over the last 10 years substantiates that physical activity and exercise also improves psychological well-being (Dubbert, 2002). It is important to clarify that much of the research presented here is correlational, which means that the scientists studied the associations that exist between exercise and mental health variables, and not the causal relationships. Published investigations conclude that individuals with improved levels of fitness are capable of managing stress more effectively than those who are less fit (Hassmen, Koivula & Uutela, 2000). The data suggest an inverse relationship: higher physical fitness is associated with lower levels of stress. It appears that the method of exercise that most benefits stress reduction is cardiovascular exercise. Studies describe the role of exercise as a preventive intervention in managing stress as opposed to a corrective intervention. The research indicates that moderate intensity aerobic exercise, performed three times a week (sessions lasting over 20 minutes) for up to 12 weeks, has the most influence on stress management. Although the specific mechanisms explaining the improved stress levels from aerobic exercise are unclear at this time, it appears that possible theories include the involvement of physiological, biochemical and psychosocial factors (Callaghan, 2004).

21) Mood State
Frequently, personal trainers and fitness professionals hear clients say that they exercise because it “feels good.” Because mood state is influenced by psychosocial, psycho-physiological, biochemical, and environmental factors, explaining the exercise-induced mechanism is quite difficult. However, it appears that cardiovascular and resistance exercise can positively affect different mood states including tension, fatigue, anger and vigor (a psychological variable defining vitality or energy) in normal and clinical populations (Lane & Lovejoy, 2002; Fox, 1999). In addition, even acute bouts of exercise may improve a person’s present mood state. It has been shown that a single bout of 25-60 minutes of aerobic exercise (at low, moderate or high intensities) increases positive mood feelings while also decreasing negative mood feelings. Implications from these data denote the incorporation of habitual exercise in a person’s lifestyle for the enhancement of a positive mood state. The use of resistance training to improve mood state requires further research.

22) Depression
The antidepressant action is one of the most commonly accepted psychological benefits of exercise. Individuals with clinical depression tend to be less active than healthy active adults and have a reduced capacity for physical exertion (Fox, 1999). As such, it is challenging for the personal trainer and fitness professional to introduce physical activity to this population, as people suffering from depression are not predisposed to participating in exercise. However, patients diagnosed with depression have credited exercise as being a most important element in comprehensive treatment programs for depression (Dunn et al., 2002). Cardiovascular and resistance exercise seem to be equally effective in producing anti-depressive effects (Brosse, Sheets, Lett, & Blumenthal, 2002). Therefore, the inclusion of resistance exercise, circuit training, calisthenics, as well as different modes of aerobic exercise should be encouraged.
It also appears that both acute exercise bouts and chronic exercise training programs have a positive effect on people with clinical depression (Dunn et al., 2002). The research does infer, though, that the greatest anti-depressive effects seem to occur after 17 weeks of exercise, although observable effects begin after 4 weeks (Scully et al., 1998). In addition, the effects of exercise on depression seem equivalent in both genders and are uninhibited by age or health status. Although no research guidelines exist for an actual exercise prescription, the evidence suggests following the ACSM guidelines for the recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness and flexibility in healthy adults (see Side Bar 1).

23) Anxiety
According to Webster’s Unabridged Dictionary, anxiety is “distress or uneasiness of mind caused by fear of danger or misfortune.” It is a stage of apprehension. The results of over 30 published papers substantiate a link between acute and chronic exercise and the reduction of anxiety (Scully et al., 1998). Most of the research on exercise and anxiety involves aerobic training regimens. The few studies involving resistance training and flexibility have also shown a slight decrease in anxiety, but additional research in this area is needed. However, the data does indicate that aerobic exercise is more beneficial for the reduction of anxiety. In reference to the actual aerobic exercise prescription, there appears to be much debate about whether low-intensity, moderate-intensity, or high-intensity exercise is most beneficial. For participant adherence, exercise intensity should be set at an adjustable level agreed upon by the individual in consultation with a personal trainer or fitness professional. It appears that even short bursts of 5 minutes of cardiovascular exercise stimulate anti-anxiety effects. The research also indicates that individuals who train for periods of 10 to 15 weeks receive the greatest beneficial effects.

24) Self-Esteem
As with the other psychological health variables, exercise has a positive influence on improving self-esteem (Callaghan, 2004). The effect of exercise also appears to be more potent in those who have lower self-esteem. Studies indicate that aerobic exercise may have a more pronounced effect than anaerobic exercise, but that may be because there is little research available on resistance training exercise and self-esteem. However, self-esteem is quite complex and studies suggest that certain subcomponents contribute to a person’s self-esteem, including perceived sport competence, physical condition, body image and strength (Scully et al., 1998). Because of the many variables that influence self-esteem, it is important to note that a person may highly value his/her physical condition and yet have a negative evaluation of his/her body. Current research provides little direction regarding the type of exercise and dose recommendation for improved self-esteem (so perhaps follow 2006 ACSM guidelines in Side Bar 1. for now). In relation to exercise, it is interesting to note that important factors influencing a person’s self-esteem are perceptions of their body attractiveness and physical condition (McAuley et al., 2000).

25) The “Weekend Warrior”
All position statements on physical activity surround their messages around the importance of consistent physical activity and exercise throughout the course of the week. Yet, a sub-population of exercisers are those who do 1 or 2 bouts of exercise a week (perhaps because of time or choice), who have been ‘affectionately’ labeled ‘weekend warriors.’ Although many hypothesis and suppositions have been suggested about the health of this subpopulation of exercises, most recently a rather large scientific investigation revealed some interesting findings. I-M Lee and colleagues (2004) found that ‘weekend warrior exercisers’ who had no major risk factors (and expended at least 1,000 kilocalories in this sporadic exercise pattern) had a lower risk of dying as compared with their sedentary counterparts. However, individuals with one or more risk factors to CHD may not benefit from this sporadic approach to physical activity, and should be encouraged to get their physical activity and exercise throughout the course of most days of the week.

Directions for the Future
As personal trainers and health and fitness professionals expand their professional direction, the core model of the programs we develop and endorse will surely be engrossed in the enhancement of health for our clients. As well, with the rapid growth of the computer and communication technologies, more education and information about health, fitness and quality of life issues is easier to disseminate to our interested and growing audience. As a profession we need to combine our creative capabilities in exercise programming with our highly developed technologies and utilize these research applications into designing new strategies to get more people, of all ages, physically active and exercising.

Side Bar 1. New 2006 ACSM Position Stand on General Exercise Programming
The following is an abbreviated summary of the 2006 position stand by the American College of Sports Medicine for the recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults.
Cardiorespiratory Fitness and Body Composition
Frequency: 3 to 5 days per week
Intensity: 55/65% to 90% of maximum heart rate 40/50% to 85% of maximum oxygen uptake (Heart rate reserve or VO2reserve)
Note: The lower intensity levels (55 – 64% of maximum heart rate and 40 to 49% of maximum oxygen uptake) are applicable for persons with low fitness levels.
12-16 ratings of perceive exertion
Duration: 20 to 60 minutes continuous or a minimum of 10-min bouts of accumulated exercise throughout the day
Mode: Dynamic activities that employ the major muscle groups of the body in a rhythmic and continuous fashion

Muscular Strength and Endurance and Body Composition
Frequency: 2 to 3 times per week
Intensity: To volitional fatigue or stop 2-3 repetitions before volitional fatigue
Sets: 1 set per exercise (minimum)
Repetitions: 3 to 20 repetitions for each exercise (e.g., 3-5, 8-10, 12-15)
Exercises: 8 to 10 exercises for the major muscle groups of the body

Frequency: 2 to 3 days per week; ideal 5 to 7 days per week
Intensity: Stretch to tightness at the end of the range of motion but not to pain
Type: Static stretches
Exercises: For all major muscle groups of the body
Adapted from American College of Sports Medicine (ACSM). 2006. ACSM’s Guidelines for Exercise Testing and Prescription, 7th Edition. Philadelphia, PA: Lippincott Williams & Wilkins.
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