For much of history, high levels of intense daily exercise was probably a necessary requirement for human survival. However, in most industrialized countries the necessity for physical activity to sustain life is declining. As a result, we are seeing a decline in physical fitness in many of these populations.
The purpose of this article is to explore the scientific literature and uncover the role that physical activity plays in the maintenance of good health and the avoidance of chronic disease. We will also discuss different types of exercise and why, for some people, exercise may not be a great option. What is Exercise?
Physical exercise refers to any bodily activity that enhances or maintains physical fitness, health, and wellbeing [ 1 ].
The idea that physical activity is important for health and disease prevention is not a new concept but has been appreciated for millennia. Indeed, Hippocrates (∼450 BC) stated that the body falls sick when exercise is deficient.
The Global Burden of Disease Study carried out by the World Health Organization included physical inactivity as one of the most important risk factors threatening global health [ 2 ].
In fact, research from the U.S. Centers for Disease Control and Prevention has attributed 23.3% of US deaths to the lack of regular exercise. Health Benefits of Exercise
1) Enhances Cognition
Exercise boosts BDNF , which increases neuronal survival, enhances learning, and protects against cognitive decline [ 3 ].
One study found that three 60 minute sessions of moderate physical activity per week increased memory. This was possibly due to increased blood flow to certain parts of the brain (hippocampus) [ 4 ].
Even in old people, aerobic exercise can increase cognition, brain size, and power [ 5 ].
Studies have shown that without a regular exercise regime the brain deteriorates and loses cognitive power much faster [ 6 ].
In fact, one study found that elderly people who engage in aerobic exercise had bigger brains. Non-aerobic yoga or toning exercises did not produce the same effect [ 7 ].
In obese children, physical activity improved executive function and mathematics test scores [ 8 ].
By supporting nerve growth, metabolism, and vascular function, exercise promotes brain plasticity [ 9 ].
Moderate physical activity increases neurotrophins, proteins that support brain plasticity (ability to change). As such, exercise is probably even more important for the young (<25), developing brain [ 10 ].
Recent studies have shown that the beneficial effects of exercise on the brain can be increased by the consumption of natural products like omega-3 fatty acids or plant polyphenols [ 11 ]. 2) Supports Heart Health
Many studies have shown that regular physical activity is associated with a reduced risk of cardiovascular disease [ 12 ].
One long-term study looked at the effects of regular exercise on men and women over the age of 73. It found that total exercise, exercise intensity, and leisure time intensity were all associated with a l ower risk of heart attack [ 13 ].
For women, the beneficial effects of exercise on the heart requires just 1 hour of walking per week [ 14 ].
Energy expenditure of 1600-2200 calories per week via exercise is needed for mild heart disease [ 15 , 16 ].
Low-intensity exercise (<45% of max intensity) improves the health of people with heart disease [ 17 ].
A recent study confirmed that regular walking is the best form of physical activity for heart health [ 18 ].
Exercise improves heart health by reducing “bad” cholesterol ( LDL ) and increasing “good” cholesterol ( HDL ) [ 19 , 20 ]. 3) Helps With Diabetes and Metabolic Syndrome
Aerobic and anaerobic training decrease the risk of developing type 2 diabetes [ 21 , 22 , 23 ].
In one study, every extra 500kcal burned per week through exercise decreased the risk of diabetes by 6% [ 24 ].
40 minutes of intense exercise per week reduced the risk of diabetes in middle-aged men [ 26 ]. Weight loss via exercise can reduce the risk of diabetes by 40-60% among overweight individuals [ 27 ].Moderate physical activity for >150 minutes per week was found to be more effective than the drug metformin [ 27 ].One study showed that diabetics who walked at least two hours per week had 39-54% lower mortality [ 28 ].Inactive men with diabetes were found to be 1.7 times more likely to die than physically active diabetics. This relationship also applies to those with metabolic syndrome [ 29 , 30 ].Resistance training (e.g. weightlifting) might help regulate blood sugar more than aerobic exercise [ 31 ]. 4) Improves Mental Health People who engage in regular physical activity experience fewer depressive and anxious symptoms [ 32 ].Both aerobic (e.g swimming) and anaerobic (e.g. weight training) exercise effectively lower depression and enhance mood [ 33 ].Individuals who maintain a reasonable level of aerobic fitness are less likely to relapse into depression [ 34 ].People with chronic anxiety often have a dysregulated HPA axis . Studies have shown that exercise improves the way the HPA axis modulates stress reactivity and anxiety [ 35 , 36 ].High levels of physical activity are associated with improved heart rate variability scores (stress resilience marker) [ 37 ].One study found that college students who exercised regularly experienced less stress and hassle than those who didn’t [ 38 ].Another study found that regular physical activity buffered the stressful effects of widowhood in elderly subjects [ 39 ].Exercise increases norepinephrine , which helps the brain deal with stress more effectively [ 40 ].In one study, both African dance (rigorous exercise) and yoga caused significant improvements in stress levels [ 41 ].As well as reducing mental stress, some forms of exercise are very effective at reducing cellular stress. For example, yoga has been shown to improve antioxidant status and limit oxidative damage [ 42 ]. 5) Boosts Sleep Quality The idea that exercise helps sleep has existed for thousands of years [ 43 ].Disturbed sleep is a common symptom of anxiety. Thus, exercise’s positive effect on sleep may be […]