March 2, 2024. If you’ve been shivering during this crazy cold winter season, you’ve been burning calories. And you’ve been doing it in a very desirable Way. You’ve been converting white fat to brown fat. Say what?
Most of your fat is probably white fat. It just sits there. It’s difficult to get rid of. But when you shiver, you produce a hormone (irisin) that converts white fat to brown fat. And brown fat does burn off. It burns calories to generate heat. To warm you up. Apparently, that’s the evolutionary advantage of shivering.
Now think about what’s happening when you shiver. Your muscles are contracting. Like when you exercise. And, yes, exercise generates that same hormone, irisin. Which, in turn, converts the undesirable, intractable white fat to the desirable, calorie-burning brown fat. Click to read the just-published study.
If you’re not an Eskimo, you probably have very few opportunities for a really good shiver. But every day’s a good opportunity to contract some muscles. And even a minute’s worth of muscle contraction every hour or two has a big effect.
“Because any type of brief, yet frequent, muscular contraction throughout the day may be necessary to short-circuit unhealthy molecular signals [from prolonged sitting] causing metabolic diseases.” American Diabetes Association, “Role of Low Energy Expenditure and Sitting in Obesity”.
Even if you exercise vigorously for an hour – five times a week – too much sitting still significantly increases your risk of all those things you exercise to avoid. Like cardiovascular disease, type 2 diabetes, metabolic syndrome risk factors, and obesity.
So get up. Pace. Fidget. Or do a little bit more, and do it deliberately throughout your day. Every day. Whether you’re on your butt staring at a computer monitor or a TV, you gotta shake your thing every once in a while. Getting up to go to the bathroom between commercials counts. But for something you can do right at your desk or on the couch, try this.
Seated leg extension
You can do this at home. You can get away with it in the office or any other workplace that puts you in a chair for the day. Press Play and watch me do it in two chairs. Or read what I say in the video:
Good posture. Sit erect, feet in front of you, flat on the floor. Use your hands to hold onto the front edge of your chair. Bend your right knee and extend your right leg out in front of you – until it’s parallel with the floor. Hold it there for two seconds – or pulse it up and down two or three times. Not a real kick – just a small movement up and down. Put your leg back down. No do it a few more times. Five or ten total. Then do it with your left leg.
You’ll feel this in your quadriceps muscles. It’s a good strengthening exercise. But most important, it gets you moving, not sitting. And it gets you to contract large leg muscles.
It’s Always Something
Just when you think you’ve got it all taken care of with your 30 minutes a day of exercise, they tell you this:
“Lean and obese people stand and ambulate ∼9 and ∼6.5 h/day, respectively. Supporting the mass of the body in combination with spontaneous movement or very slow ambulation (1 mph) raises whole-body energy expenditure 2.5-fold more than when seated still. Nonexercise movements decrease significantly as people age and become more sedentary. Thus, given the small differences in daily energy balance necessary to explain weight gain over many years, it is plausible that postural allocation [translation: whether you’re standing or sitting] plays a role in human obesity.”
Studies at the molecular level found that “the expression of many genes were “switched on” and dozens of genes “switched off” during local contractile inactivity in postural muscles in the leg.” Turns out that prolonged sitting affects “regulation of skeletal muscle lipoprotein lipase (LPL) (a protein important for controlling plasma triglyceride catabolism, HDL cholesterol, and other metabolic risk factors).” And it affects it in ways that put you at risk:
“Middle-aged men who had to sit many more hours per week and obtain less physical activity had greater risk for premature myocardial infarction [heart attack] and mortality from coronary artery disease. These general findings were subsequently confirmed in studies in middle-aged women and an elderly group.”
All of the above quotes are from the American Diabetes Association, “Role of Low Energy Expenditure and Sitting in Obesity”.
