What happens with too little exercise?
A lack of physical activity can cause its own problems. An overload of unremoved wastes, clogged channels, or dense and slow qualities can begin to shroud the body and soon the mind as well. This is most likely in those with earth and water constitutions who can happily remove some moisture (mucous) by sweating and are likely to sweat more profusely once they get going. Exercise is the #1 management for Kapha types, in my experience. Coupled with a lighter diet, these folks enjoy the strongest of body types that withstands all sorts of stressors.
The season is an important factor, because hot weather makes the body tired, where cold weather makes the body stronger, but also harder and slower. Exercise is more important for warmth and circulation in winter and spring. Funny thing is, living in a cold place, I notice how many people stop exercising in winter, then dust off the sneakers and get back outside in warm weather. Managing a long winter, exercise is key, and will make the heavy, damp spring season much lighter.
The right amount of exercise should feel refreshing, not tiring. The ideal of “fitness” in Ayurveda probably looks like a LOT less movement than you think.