Increase metabolism to improve basic fitness

Large muscle exercise is effective for improving basal metabolic rate.

Working a deskwork job and not exercising.
Tend to eat too much.
Those decrease basal metabolic rate more easily as we get older.

There is no way to avoid the fact that basal metabolic rate declines with aging.
The important thing is to exercise large muscles.

Large muscles include:
Greater Pectoral muscles (chest)
Latissimus (back)
Gluteus maximus (butt)
Quadriceps and hamstrings (legs)
Calf muscles

Working these muscles increases energy consumption and generates body heat.

Crossfit has a vast range of menus working out these large muscles. Instead of working any one specific muscle, Crossfit promotes the balanced training of large muscles throughout the body.