Moderate exercise, such as walking 30 minutes a day, may offer better protection against diabetes and heart disease than a more rigorous workout regimen, concludes a study in the Journal of Applied Physiology.
What's more, some of the benefits achieved through moderate exercise seem to last much longer than the benefits gained through more intense training.
Exercise physiologist Cris Slentz, of Duke University Medical Center looked at 240 middle-age, sedentary people and divided them into four exercise groups: high amount/high intensity; low amount/high intensity; low amount/moderate intensity; and a control group that did no exercise.
Training consisted of a gradual increase in amount of exercise followed by six months of exercise at the prescribed level. They exercised on treadmills, elliptical trainers, or stationary bicycles.
The researchers found that no amount of exercise significantly changed levels of low- density lipoprotein (LDL -- "bad" cholesterol). However, length and intensity of exercise did improve levels of high-density lipoprotein (HDL -- "good" cholesterol), and that benefit was sustained over time.
The study also found that those who engaged in moderate intensity exercise -- the equivalent of walking 19 kilometres a week -- lowered their levels of triglycerides by about 25 per cent.
This was twice as much as the hard-intensity group, who performed the exercise equivalent of jogging 32 kilometres a week.
They maintained that benefit for 15 days, while the triglyceride levels of the more vigorous exercisers rose after five days without exercise.
"A proper exercise program appears to be able to lower a person's insulin resistance in just a matter of days," senior author and cardiologist Dr. William Kraus said. "We were also amazed to see that the lower triglyceride levels stayed low even two weeks after the workouts ended."
The good news is that moderate exercise has a lot of benefits, said Slentz. "On the other hand, vigorous exercise increases cardiovascular fitness."
