Psychosomatic Medicine Journal: Regular exercise has a real and significant effect on depression. According to 16-week study on 202 depressed men and women age 40 and older, the findings demonstrate that those who went through group-based exercise therapy did as well as those treated by an antidepressant.

The Mayo team: Exercise may guard against mild cognitive impairment through production of nerve-protecting compounds, increased blood flow to the brain, improved development and survival of neurons, and decreased risk of heart and blood vessel diseases.

Dr. Mercola: Exercise encourages your brain to work at optimum capacity by causing your nerve cells to multiply, strengthening their interconnections and protecting them from damage. Lab tests on animals have shown that during exercise, their nerve cells release proteins known as neurotrophic factors.

Arthritis Care & Research: After eight weeks, people in the exercise group doing the Arthritis Foundation Regimen of exercises showed significant improvements in pain, fatigue and managing arthritis. The pain and fatigue improvements were still evident six months after completing the exercise program. Weight-bearing exercises are another way to help maintain bone health.

The American Academy of Orthopaedic Surgeons: Recommended forms of weight-bearing exercise: Brisk walking, jogging or hiking; strenuous yard work such as pushing a lawn mower, or active gardening; sports such as soccer, basketball, baseball, tennis or racquetball; climbing the stairs, step aerobics or dancing; skiing, bowling, skating or karate; use of free weights or weight machines.

Breast Cancer Research Journal: Vigorous activity can reduce the risk of breast cancer by about 30 percent in normal-weight women, according to an 11-year U.S. study of 32,269 postmenopausal women.

Various Medical Experts at AMA: Regular workouts may help fight off colds and flu, reduce the risk of certain cancers and chronic diseases, and slow the process of aging. A growing body of research is showing that regular exercise can boost your body's immune system, increasing the circulation of natural killer cells that fight off viruses and bacteria. Regular exercise has also been shown to combat the ongoing damage done to cells, tissues and organs that underlies many chronic conditions. Studies have found exercise can lower blood pressure, reduce bad cholesterol, and cut the incidence of Type 2 diabetes. Medical experts say inactivity poses as great a health risk as smoking, contributing to heart disease, diabetes, hypertension, cancer, depression, arthritis and osteoporosis. 

BMJ Specialist Journals: A person who maintains aerobic fitness may delay biological aging by up to 12 years.

Daniel M. Landers, Arizona State University: Best treatment results for anxiety are seen through aerobic exercise. Best results for reduced depression are seen with more vigorous exercise and sports activity. Both anxiety and depression benefits through exercise and sports are similar to other medical treatments. Physical activity was also associated with an increase in positive self esteem, restful sleep and better stress response.

SportandDev.org: The positive, direct effects of engaging in regular physical activity are particularly apparent in the prevention of several chronic diseases, including: cardiovascular disease, diabetes, cancer, hypertension, obesity, depression and osteoporosis.

United Nations Inter-Agency Task Force on Sport for Development and Peace: Young people can benefit from physical activity as it contributes to developing healthy bones, efficient heart and lung function as well as improved motor skills and cognitive function. Physical activity can help to prevent hip fractures among women and reduce the effects of osteoporosis. Remaining physically active can enhance functional capacity among older people, and can help to maintain quality of life and independence.

Donna Martini: It makes you feel good about life. Go out, play and have a nice day!