A recent study followed 105,677 participants from 21 countries for an average of 11 years, and found that those who sat for 6-8 hours a day had a 13 percent increased risk for early death and heart disease, while those who sat for more than eight hours a day had a 20 percent increased risk (JAMA Cardiol, published online June 15, 2022). Furthermore, those who sat the most and exercised the least had a 50 percent increased risk, while those who sat the most and exercised the most had only a 17 per cent increased risk.

Prolonged sitting also increases risk for strokes, high blood pressure, high cholesterol, type 2 diabetes (Am J Lifestyle Med, 2020 Mar-Apr; 14(2): 204-215), high triglycerides, increased waist circumference (PLoS One, 2012;7:e311320), and damaged arteries (Med Sci Sports Exerc, 2015;47:843-849).

An earlier study using accelerometers found the average sitting time of older adults is more than 7.7 hours/day (Am J Epidemiology, 2008;167:875-81). When asked how much they sat, people under-reported their time by an average of 4.7 hours/day (J Sci Med Sport, 2014;17:371-5).

Sitting is Harmful for Non-Exercisers at Any Age
Older people who move around live longer than those who are consistently sedentary, and sedentary older people who become more active live longer than those who remain sedentary (Med Sci Spts Ex, Aug 2013;45(8):1501-1507). The more time people sat, the more likely they were to:
• have a big belly (a sign of high blood sugar levels)
• have high blood pressure
• have high HBA1C blood test (a measure of high blood sugar)
• have a high CRP blood test (a measure of inflammation)
• have higher blood sugar levels
• have heart disease
• have diabetes
• be a smoker
• be overweight

Exercise Helps to Prevent Harm From Prolonged Sitting
To protect yourself from the health consequences of sitting for long periods, try to spend more time moving around, exercise in your favorite activities, and work to increase the intensity of some of your exercise. A review of 16 studies covering more than a million people, showed that prolonged sitting during working, commuting or leisure time is associated with increased risk for premature death and that this risk was eliminated completely by 60 to 75 minutes of daily moderate-to-vigorous physical activity, and was reduced by exercising just 25 minutes per day (Lancet, July 27, 2016;388:1302-10).

Little or No Benefit from Standing
Standing for long periods of time may be even worse than extended sitting (Saf Health Work, Mar 8, 2012;3(1):31-42). A study of 7,300 workers found that those who stood at work were twice as likely as those who primarily sat to suffer from heart disease during a 12-year period (American Journal of Epidemiology, Jan 2018;187(1):27-33). Standing for extended periods is not likely to protect you from the increased risk for obesity, diabetes and heart attacks because there is very little metabolic difference between sitting and standing. See Standing Is Not Much Better Than Sitting

My Recommendations
You do not need to have a specific exercise program to stay fit; you just need to keep on moving for a large part of each day. It is healthful to mow your lawn, wash your dishes, make your bed, vacuum your house, go for a walk, and participate with your friends in activities where you are moving your arms and legs – dancing, cycling, swimming, running, nature walks and so forth.

To gain maximum health benefits from your skeletal muscles, I recommend including some sort of resistance exercise. If you are not already doing strength training, first check with your doctor to make sure you do not have any condition that may be harmed by exercise. Then join a gym and get instructions on how to use the weight-training equipment, or work with a personal trainer to plan a program you can do at home. Since lifting heavier weights is far more likely to injure you than lifting lighter weights, I recommend that you lift lighter weights with far more repetitions. Older people, in particular, can use each specific weight machine and lift and lower a lighter weight up to 100 times in a row. Stop that exercise when the muscles start to feel tight or hurt.

Caution: Intense exercise can cause a heart attack in a person who has blocked arteries or heart damage. Check with your doctor before you start a new exercise program or increase the intensity of your existing program.