Saheb Sahu, FAAP, MPH.
Reading is to the mind what exercise is to the body. – Joseph Addison
The evidence is clear—physical activity (exercise) can make you feel better, function better, and sleep better. Even one session of moderate-to-vigorous physical activity reduces anxiety, and even short bouts of physical activity are beneficial. We know without a doubt, for instance, that exercise lowers the risk of heart disease, some cancers, premature mortality, and even overall cause of mortality. We know it lowers blood pressure and reduces dangerous blood clots. We know it prevents diabetes, improves brain function, and spurs muscles to make hormones that dampen chronic inflammation and much more. Being physically active also fosters normal growth and development, improves overall health, and can reduce the risk of various chronic diseases.
Types of Exercise
There are two main types of exercises- Aerobic Activity, and Muscle Strengthening. Aerobic exercise uses the large muscle of the legs and arms in a continuous fashion. Aerobic fitness is also called cardiovascular fitness because it improves the ability of the heart, blood vessels and lungs to supply oxygen and fuel to the body. Aerobic exercises are: Walking, running, bicycling, swimming, dancing, skipping ropes, stair climbing, rowing and cross country skinning.
Muscle strengthening exercises build muscles and go by a variety of names, including strength training, resistance training, and weight training. These exercises increase muscle strength, and flexibility, build bone strength, improve balance and reduce the risk of breaking bones. They also improve cardiovascular health, help in weight loss and prevent diabetes.
Exercise: How Little, How Much?
Even very little exercise is better than nothing. If you’re a runner, just 5-10 minutes a day at relatively slow speeds (less than six miles an hour) is linked to a markedly reduced risk from all cause and cardiovascular (heart and blood vessels) mortality. Interestingly, a 5 minute run is as good as a 15-minute walk. But even a brisk walk for 15 minutes a day reduces all cause mortality and provides an extra three years of life expectancy. Astonishingly, just one hour of running can add seven hours to your life.
All you have really to do for better health and increased longevity is meet the US Government’s CDC and the World Health Organization’s minimum activity guidelines: 150 minutes a week of moderate exercise or 75 minutes a week of vigorous activity.
Sitting Kills
To put bluntly, sitting kills. Indeed, physical inactivity causes as many deaths a year globally as smoking. A sedentary life style not only raises the risk of getting many chronic diseases, but increases the severity of these diseases and the risk of dying from them as well. It gets worse. A sedentary life style is also linked to metabolic syndrome( high blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol) gallstones, asthma, chronic obstructive pulmonary disease (COPD),some cancers, cognitive dysfunction, dementia, osteoarthritis (joint pain), low back pain, fragility, constipation and muscle weakness and decreased functional independence.
Physical inactivity, including sitting, is lethal and so common that it now accounts for an estimated 6 million deaths worldwide.
Exercise and Heart Disease
Exercise produces its beneficial cardiovascular (heart and blood vessels) effects through a variety of mechanism. Exercise improves the size of the heart (stronger heart muscles), lowers blood pressure, regulates heart rate variability, and improves the lining of the blood vessels, decreases clogging of the arteries by lowering cholesterol and inflammation. Diabetes significantly raises the risk of heart disease, stroke and kidney failure. Exercise reduces the risk of developing diabetes as well as helps in controlling its multiple complications.
Multiple studies have shown that exercise may actually be better for people with clogged arteries than surgically implanted stents. People with chronic heart failure also benefit from regular exercise. A large study of heart failure risk, Swedish researchers followed 34,000 men and 31,000 women aged 45-83 for 13 years. Being physically active for more than 150 minutes per week, along with not smoking, having normal weight and eating modified Mediterranean diet, dramatically reduced the risk of heart failure.
The best way to increase cardiovascular fitness is aerobic exercise that involves major muscle group’s things like jogging, cycling, swimming, and dancing. Ideally, exercise should be of moderate to vigorous intensity and should be done at least five times a week for 30-60 minutes each time. The good news is that even, 15 minutes a day of moderate intensity exercise yields significant heart and longevity benefits.
Diabetes
Why is diabetes so bad? Unlike heart disease or kidney disease, in diabetes, it is your whole body that is involved. Diabetes is basically a failure of the body to control blood sugar. Diabetes harms your blood vessels, heart, kidney, brain, and nerves. At least 68 percent of older people with diabetes die from some form of heart disease, and 16 percent die of stroke.
Both aerobic and resistance training can increase glucose uptake in muscle cells and making muscles more sensitive to insulin (the hormone which controls blood sugar). Not surprisingly, highly fit people have better blood sugar control than less fit people. And ponder this: Sitting around after a meal triggers a spike in blood sugar. But getting up after a meal can cut such spike in half. In other words, it pays to get up and wash the dishes or walk the dog.
Obesity
Obesity is defined as a body mass index (BMI) of 30 or more. Overweight is defined as a BMI between 25 and 30. Obesity is now the fifth leading risk factor for mortality worldwide.
The exact physiological causes of obesity are complex. But the basic culprit is no brainer: too much food and too little exercise= energy imbalance. You cannot lose weight just by exercising. You have to do both, eat less and exercise more.
Obesity increases the risk of heart disease directly. It is a significant risk factor for diabetes. Obesity, especially abdominal fat, is a major hallmark of metabolic syndrome, a cluster of problems including hypertension, poor lipid profile, and insulin resistance. Exercise improves all the components of the syndrome. Vigorous exercise suppresses the hunger hormone, ghrelin, and increases the appetite-suppressing hormone, peptide YY.
Blood pressure
More than 70 percent of older people have age related stiffening of the larger arteries, which leads to hypertension (high blood pressure). Hypertension is a powerful risk factor for stroke (bleeding in the brain), heart disease and heart failure, and kidney disease. In fact hypertension is a leading risk factor for death, accounting for almost 13percent of total deaths in the world. In 2017, the American College of Cardiology announced a new definition of hypertension-130/80 –instead of 140/90.
The good news is that regular aerobic exercise, in older as well as younger people, decreases the stiffness in blood vessels and triggers nitric oxide, which leads to better blood flow and lower blood pressure. Even low intensity exercise such as walking can reduce blood pressure somewhat. Large prospective studies have shown that fitness is strongly linked to lower blood pressure, regardless of body weight.
Reduce Inflammation
One of the most important things that exercise does is reduce inflammation all over the body, including in the cardiovascular system. Doctors measure inflammation with a blood test called CRP(C- reactive protein), which goes up with inflammation. Elevated CRP is associated with a higher risk of heart attack, stroke and death in both healthy people and those with heart disease. Exercise can lower CRP significantly, often by as much as 20-30 percent. In one study, people in the most- fit group had 80 percent lower levels of CRP. In a study of 14,000 most active people had a CRP levels almost 50 percent lower than sedentary people.
Sarcopenia
Sarcopenia, which means loss of muscle mass, is an all-too common feature of aging, though it’s really caused by disuse, not the sheer passage of time per se. Muscle weakness and loss of muscle mass is a set up for many of the sad events of later life-falls, broken hips, disability, loss of independence, and, in many cases, the need for a nursing home. People over 50 lose on average one pound of muscle every year.
But that is what happens without strength training, also called resistance exercise or weightlifting. With strength training, older people can significantly offset sarcopenia running won’t do it. In addition to boosting muscle mass, resistance exercise can be effective antidepressant in older people. It can also help in blood sugar control in diabetic people.
And perhaps most important, strength training can improve older people’s ability to get out of a chair or off the toilet, climb stairs, bathe, prepare meals, and generally take care of themselves.
Osteoporosis
Osteoporosis means “porous bone”. It is a disorder in which bone mass is decreased, causing the bones to become fragile and leading to fracture. It affects both male and female over the age of 50. It is more common in women.
Exercise in later life can slow the rate of bone loss, but it can’t really rebuild bone. Exercise does have a small effect on strengthening the bones, but these effects are modest. In a study of 61,200 postmenopausal women, researchers found that the risk of a hip fractures was lowered by 6 percent for each increase of one hour per week of walking. Walking for at least four hours a week was linked to a 41 percent lower risk of hip fracture.
In fact, many old people without osteoporosis fall and get fracture because of weak muscles, poor balance, poor physical functioning, and general frailty. Hip fractures are particularly common and deadly in women, but men get them, too.
Some medications, including blood pressure pills, heart drugs, diuretics, tranquilizers, and opioid pain medicines, can make you dizzy and more prone to falls.
To prevent fall install handrails on stairways and toilets, and make sure there is good lighting. Don’t leave objects and rugs in areas where you walk. Get up slowly from sitting or lying- getting up quickly temporarily lowers blood pressure and raises the risk of falls. Use cane or walker if need be.
Exercise and Cognition
The ability to remember, learn, think, and reason are skills referred to collectively as cognition.
It is not news that the brain begins to decline as we age, starting, sad to say, in midlife, and sometimes earlier. Cognitive tasks that demand fluidity, such as reasoning, as well as tasks that can’t be solved on the basis of personal experience, decline. It takes longer to process information. The volume of gray matter shrinks. The hippocampus (the memory center) gets smaller, too. Blood flow to the brain decreases. On the other hand verbal knowledge and comprehension stay fairly strong throughout life.
But the good news is that, there is overwhelming evidence that regular exercise, especially the aerobic kind, can slow cognitive decline. Exercise helps keep the brain healthy well into later life, helping maintain brain volume and brain functions in specific regions. To improve cognitive functions, one way is to exercise at moderate intensity for 45- 60 minutes per session on as many days a week as possible. Aerobic exercise seems to have its biggest benefits in protecting executive function (working memory, flexible thinking, and self control) the very function most sensitive to aging.
The bottom line, exercise is the best thing going to protect the brain.
Exercise and Mood
There is no question that exercise improves mood and reduces depression, especially if you exercise outdoors in nature. In 2013 the Cochrane Collaboration, international researchers, examined 35 studies and concluded that physical activity was comparable to psychotherapy and medicine(antidepressants) at relieving depression. In 2016 meta-analysis of 25 randomized controlled trials, researchers concluded that the data showing the effectiveness of exercise for treatment for depression is extremely strong.
Exercise seems to be somewhat but not dazzlingly effective at reducing anxiety.
Exercise and Cancer
It is estimated that, worldwide, 25 percent of all cancers are caused by being overweight or obese and having sedentary life style.
Overall, the link between exercise and reduced cancer risk seems to be dose dependent the more exercise you do, the better your chances of escaping cancer. There is strong evidence for the protective effects of exercise for breast and colorectal cancer, for instance, but less strong evidence for prostate, endometrial (uterine), and lung cancer. There is also strong evidence that exercise may help in survival and better quality of life for people withcancer.
Determining Your “Fitness Age”
VO2max is a commonly used measure of aerobic fitness that basically shows the highest rate at which your body can supply oxygen to your contracting muscles.
Short of having a cardiac stress test on a treadmill at a medical facility, you can make some reasonable estimates with a few simple measurements at home. One way is to use the online methodology developed by researchers at the Norwegian University of Science and Technology. Visit web site www. ntnu.edu/cerg/vo2max or visit the Mayo Clinic website: www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/fitness/art-20046433
Conclusion
There is an old saying that exercise won’t necessarily help you live longer but it will help you live younger longer. Research has shown that increased level of fitness can boost longevity and reduce mortality rates from many causes of death: Heart disease, stroke, diabetes, some cancer and even all- cause mortality. Regular exercise helps youfrom becoming frail and losing your independence. It also improves your brain functions.
There is no doubt that sedentary life style is very harmful for overall health and wellbeing. Even very moderate exercise is better than nothing. Even a brisk walk for 15 minutes a day reduces all cause mortality and provides an extra three years of life expectancy.All you have to do is to meet the World Health Organization’s minimum activity guidelines: 150 minutes a week of moderate exercise or 75 minutes a week of vigorous activity. A 2011 analysis of 80 studies involving more than 1.3 million adults nailed the case: Higher levels of physical activity were linked to lower all-cause mortality, with the biggest benefit linked to the most vigorous activity.
Sources
- Judy Foreman. Exercise Is Medicine- How Physical Activity Boosts Health and Slows Aging. Oxford University Press; New York, 2020
- Center for Disease Control and Prevention. www.cdc. Gov/physical activity
- World Health Organization- www.who.int