You know you need your cardio to keep your heart healthy, right? So just how many hours of cardio do you need to do a week? It turns out the answer may not be one of time spent, but of intensity of exercise. A new study published this week in the American Journal of Physiology's Journal of Regulatory, Integrative & Comparative Physiology investigated the relationship between high intensity training and cardiovascular health. Their findings? Start sprinting.
The study, conducted by Mark Rakobowchuk at McMaster University in Canada, gave male and female subjects six-week training sessions using two different types of exercise. One group used high-intensity sprint training, but an overall low volume of exercise: They performed four to six sprints of 30 seconds each, separated by 4.5 minutes of recovery, and did this program three days per week. The other group did 40 to 60 minutes of moderate intensity cycling (at 65 percent of their maximum) on a stationary bike five days per week—a traditional endurance program. The study found that the groups received the same reparative benefits to their arterial systems—despite the huge difference in the actual amounts of time spent exercising.
The researchers tracked both groups for the elasticity of both their central and peripheral arterial systems—that is, blood flow to the heart, and blood flow to the muscles. They found that arteries are aided by both high-intensity training and endurance training. This finding offers new options for addressing the complexities of constricted arteries, a major cause of cardiovascular disease.
"As we age, the arteries become stiffer and tend to lose their ability to dilate, and these effects contribute to high blood pressure and cardiovascular disease," Maureen MacDonald, an associate professor in McMaster University's Department of Kinesiology told Science Daily. "More detrimental is the effect that blood vessel stiffening has on the heart, which has to circulate blood."
The implications of this research are significant, given the difficulties of persuading most people to do cardio exercise 45 minutes a day, five days per week. But smaller, less time-consuming (though very challenging) doses of exercise may be more manageable, and still give significant benefits to stiff and constricted arteries. For people from the ill to the busy to the merely tired, this research potentially offers a new, less time-consuming way to approach exercise and heart health.