It’s that time of year again. The New Year’s resolution to work out and get in shape tops many people’s lists at the beginning of January. Unfortunately, new habits are difficult to form, and motivations begin to waver right about now. In order to encourage that not to happen, let’s take a look at how our bodies respond to both activity and inactivity, from the perspective of the muscles that allow us to get moving.
It helps to keep in mind that humans (and other mammals) evolved in an environment where our survival depended on being physically active. We had to run around every day hunting and gathering, and avoiding being the hunted. Our present world isn’t “normal” in this respect, and our bodies suffer serious consequences from being sedentary. Our muscles expect to be used often, and when they aren’t, they become smaller and weaker and are easily fatigued. Once this happens, even light physical activity feels truly taxing. The years pass and soon your risk increases of succumbing to cardiovascular disease, type 2 diabetes and metabolic syndrome, various cancers and other diseases. Mental health and mood, physical appearance and bone density suffer. Fortunately, exercise is more powerful than any pharmaceutical and may reverse or stave off these ailments — you just need to do some work.
Getting over the initial burdensome hump of changing habits and, perhaps, breathlessness and soreness that comes with being more active, will result in positive changes in your muscles. The physical activity that seemed so difficult at first will get easier. Current recommendations are for about 30-60 minutes five days per week of moderate intensity exercise. Once our muscles adapt to their new active status they become a little bigger, stronger and fatigue-resistant. In turn, the rest of your body will be rewarded — from your heart and circulatory system to your metabolic systems and brain. The state of being active is, from an evolutionary perspective, the default state our muscles are intended for. Our muscles “love” to be used. If you have a dog, ask her if she likes to go for a walk and you will get an unbiased perspective on whether this is true. Dogs are built to run, and so are we.
Extensive research has led to specific recommendations for combinations of different types of exercise — aerobic, resistance, and flexibility training. The Centers for Disease Control and Prevention (www.bit.ly/2jxVpne) and the America College of Sports Medicine (www.bit.ly/1MrE3nR) have published guidelines that are easy to understand and, hopefully, implement. It’s a great place to start. If you have a chronic health condition be sure to talk with your doctor about the amount and type of activity that is right for you. If you are not inclined to join a gym or set aside 30 minutes a day for a brisk walk, you can still obtain some of the benefits of exercise by building in a little more activity into your daily routine. Take the stairs instead of the elevator. Park your car further away from a building’s entrance so you can walk more. In fact, recent research has shown that sitting for eight hours in a day could outweigh the benefits we get from exercise. So at the very least avoid sitting for more than 30 minutes at a time. Standing intermittently at your desk will initiate signals in your leg muscles to counteract uninterrupted periods without any stimulation.
So do your muscles, and yourself, a favor — and start using them more.
Clay E. Pandorf is an assistant professor of physiology at Mercer University medical school.