Exercise and physical activity fall into four basic categories—endurance, strength, balance, and flexibility. Most people tend to focus on one activity or type of exercise and think they're doing enough. Each type is different, though. Doing them all will give you more benefits. Mixing it up also helps to reduce boredom and cut your risk of injury.
Though each type is described separately, some activities fit into more than one category. For example, many endurance activities also build strength. Strength exercises also help improve balance.
Endurance- dancing
Strength- Lift weights
Balance-standing on one foot
Flexibility-yoga
We get tired after exercise because our muscle fibers get tired very quickly. This is due to the major source of energy for the muscle tissue, called adenosine triphosphate, or ATP. As the muscles make use of this supply of energy, they get tired and fatigue.
Maybe you have allergies since the weather is getting warmer or the flu
