In Act4Life, we investigate physical activity in relation to various areas of focus.
Adipose tissue blood flow is increased during exercise and adipose tissue releases energy for the working muscles in the form of free fatty acids. Adipose tissue mass is most often reduced in response to physical training and although insulin-stimulated glucose uptake in adipose tissue does not seem to be increased by an exercise intervention in humans, other metabolic pathways as well as adipokine production are affected.
Half of the Danish adult population is overweight. To perform physical exercise might be difficult for people with severe obesity, but most people are only moderately overweight and might be able to control their body weight by regulation of the physical activity level. Both people with severe obesity and with moderate overweight can markedly benefit of regular physical exercise.
Metabolic health is markedly improved by physical exercise. The abdominal fat mass is reduced and the peripheral insulin sensitivity and HDL-cholesterol are increased. In addition, in some populations the blood pressure and plasma triacylglycerol are decreased. Weight loss via diets can also influence metabolic health beneficially in people with overweight, but exercise-induced weight loss can convey additional beneficial effects.
Calories are expended during exercise. However, to expend a significant amount of calories it takes a significant amount of exercise. One kilo of fat contains approximately 10.000 kcal, and this amount of calories would require approximately 20 hours of vigorous intensity exercise to expend. When the body is pushed into a negative energy balance, compensatory mechanisms are initiated which might limit weight loss.
A myth says that you cannot lose weight via physical exercise as appetite is increased by exercise, but this does not seem to be true – at least in the short term. Three months of daily vigorous intensity exercise do not increase energy intake, appetite sensations or hormones known to stimulate appetite in overweight men and weight loss equals energy expended during physical exercise.
If the pill is not taken, you do not obtain the benefits. This is also true for physical exercise. The challenge therefore is to incorporate a significant amount of physical activity into the various domains of everyday life. Most people exercise in their leisure time, but exchange of passive with active commuting is an additional way of incorporating physical activity into everyday life.
In the woman's menopause, estrogen production has ceased, and body morphology changes from ‘pear’ to ‘apple’ form due to accumulation of adipose tissue around the internal organs in the abdominal cavity, which is associated with negative health changes. Regular physical exercise helps to stabilize energy balance and conveys the same health benefits in post- as in premenopausal women.
Is technology friend or foe for physical activity? Technology has manufactured physical activity out of our daily lives. However, activity apps and smart watches can be used to monitor and motivate physical exercise.
Not all people respond in the same way to physical activity. Nevertheless, current activity recommendations of ‘at least 30 minutes per day’ are based on a ‘one size fits all’ approach. Identification of phenotypic and genetic predictors that underlie the inter-individual variability in response to physical activity can be used for personalized planning of exercise.
Physical activity during pregnancy is recognized as a healthy behavior, since it improves various health parameters in mother and child and reduces risk of complications during pregnancy and delivery. Pregnancy may therefore constitute a ‘window of opportunity’ for increasing the women’s physical activity level if the health care system offers facilities or programs that motivate and support the pregnant women to be physically active.