Exercise

Exercise is "physical activity which is usually regular and done with the intention of improving or maintaining physical fitness or health."

Types of physical activities

Usual daily activities

General physical activities may be defined in terms of the intensity levels .

"Neighborhood physical and social environmental factors are significantly associated with walking at recommended levels."

Signs placed in public places where steps are available may increase usage of the stairs.

Moderate to high intensity exercise

(in progress)

Metabolism and energy

Energy consumption

The amount of energy expended with exercise, or the work, is measured in calories. Using running as an example:

$kinetic\ energy={\frac {1}{2}}*mass*velocity^{2}$

$work=\ force*distance$

In running, work is directly dependent on:

• Body weight
• Duration

Work is indirectly dependent on:

• Speed

Effects of exercise

Effects on Hypertension

Exercise programs that primarily involve endurance activities prevent the development of hypertension and lower blood pressure (BP) in adults with normal BP and those with hypertension .

Insulin sensitivity

(in progress)

Insulin production

Aerobic exercise was shown to increase beta cell function in older persons, in whom both insulin production and insulin sensitivity are frequently impaired.

Mood and cognition

The effects of exercise on mood and mental functioning, described by the latin quotation Mens sana in corpore sano (a healthy mind in a healthy body), are profound. Research attempting to isolate the biochemical nature of this relationship showed that the access to the brain of the insulin-like growth factor I (IGF-1), which is stimulated by physical activity, could explain much of the beneficial effects of exercise. It is apparent that exercise lessens anxiety and increases cognitive skills by stimulating the birth of new neurons, neurogenesis, in the hippocampus, and that this process is in large part mediated by IGF-1.

As little as 20 minutes of exercise per week is associated with improved mental health.

Harm reduction

Considering the magnitude of the health effects of exercise, it is justified to enquire if this strategy can act as protective measure against the harm associated with a variety of unhealthy practices that patients are unable or unwilling to abandon. Harm reduction is a pragmatic approach to medical and psychological care that seeks to address the needs of such persons, instead of focussing only on coercitive and poorly effective approaches to unhealthy behaviours, most notably addictions. It appears that engaging in higher physical activities neutralizes many of the deleterious effects of tobacco smoking. Tobacco addiction in itself leads to a tendency to physical inactivity, a fact that should reinforce the need to investigate the health effects of exercise and promote its value in tobacco addiction, the major cause of lung cancer.

Mortality

Physical fitness, as measured by maximal treadmill exercise test duration, correlates with longevity in the elderly as well as both longevity and functional status.

Promoting exercise

Use of a pedometer is "associated with significant increases in physical activity and significant decreases in body mass index and blood pressure" according to a systematic review.