While my main focus is on nutrition and health, I do keep in mind that the best companion of good eating is staying “active”! Unfortunately I am not a fan of long hikes and running marathons, yet my activity hobbies (whether zumba, swimming, or yoga) are continuous and keep me moving. Personally, I think it is unwise to focus either on food or physical activity solely (I believe food can lead specifically to stronger body weight management outcomes than activity, but we shall discuss it later), but luckily taking care of one usually results in improvement in both (from what I have observed).
Sit down & Relax
Currently, public health recommendations encourage people to engage in 30 min per day or 150 min per week of moderate-to-vigorous activity, and this represents only 3% of the time we spend awake. That is really not that much, and indeed used to be very easy to achieve without any conscious effort.
However, more&more studies on the issue of sedentary behavior (TV watching, dissertation writing 0_0) are emerging and might need their own recommendations. There is evidence that sedentary behavior has a negative independent effect on health (so, you might be going to the gym 5 times a week, but if you are sitting most of the rest of your time this leads to poor health regardless of all that gym time).
Definition: The term sedentary behavior (from the Latin word sedere, “to sit”) describes a distinct class of activities that require low levels of energy expenditure in the range of 1.0–1.5 METs (multiples of the basal metabolic rate) and involve sitting during commuting, in the workplace and the domestic environment, and during leisure.
Unfortunately, being sedentary is as natural as it gets these days- I, for instance, drive to campus and spend hours sitting in classes or in my office working on research.. I try to take a break to walk around, I try to go to the gym..but that might not mitigate the 5+ hours I have to spend simply SITTING :/. [and I am typing this from a library, where I plan to spend most of my Sunday..]
Currently, optimal levels of sedentary behavior to recommend the public are not known.
Not too many methodologically-strong studies are available yet, but time spent in sedentary behavior has been shown to be consistently associated with increased risk for all-cause, CVD-related, and all-other-causes mortality in both men&women independent of body mass index and physical activity. (caution: still only 6 studies to date)