Loss of muscle mass, decreased bone density and a decline in cardiovascular fitness: all of these are natural side effects of growing older.
These effects also happen to be associated with extended periods of time spent in space, as astronauts have nothing to work against in the absence of gravity.
Naturally, astronauts need to stay healthy and fit in space, and those of us here on Earth want to stay healthy and fit so we can live longer while maintaining a high quality of life.
To determine how the loss of muscle, bone and cardiovascular fitness can best be prevented while astronauts work in space, NASA’s recently completed Human Research Program Integrated Resistance and Aerobic Training study, or “iRAT,” investigated the value of high intensity training.
According to NASA, the study consisted of three randomized groups: a control group that performed no exercise, one group that exercised daily and another comprised of all males that exercised daily and received daily testosterone treatments.
“The ground study participants remained in a six-degree head-down tilt to simulate the fluids shift of spaceflight throughout the 70 days, even during exercise,” NASA reporters Monica Edwards and Laurie Abadie explained.
Essentially, the subjects spent the entire duration of the study in a “bed rest” position.
The exercise groups were prescribed a schedule that included three days of weight training and six days of aerobic exercise, alternating between high-intensity interval training and steady-state, continuous cardio workouts.
The high intensity interval workouts were performed at maximal or nearly maximal efforts: some were maximal effort treadmill sprints that lasted only 30 seconds and others were less intense, but all ranged from 70 to 100 percent of maximal effort.
The results showed that the combination of high intensity interval workouts and weight lifting, along with a balanced diet (all of the subjects followed a diet consisting of 55 percent carbs, 30 percent fat and 15 percent protein), helped to prevent “muscle atrophy, bone loss, and cardio deconditioning.”
For astronauts, this means following such a workout regimen can help to combat loss of physical fitness and bone and muscle mass while working for extended periods in space.
Dr. Lori Ploutz-Snyder, lead scientist for NASA’s Exercise Physiology and Countermeasures said this study (along with another called Sprint, which is evaluating such exercise programs on astronauts aboard the space station) will help the team at NASA develop effective exercise regimens for long-duration space missions of even up to three years.
And for the rest of us here on Earth, the results of the study will likely first benefit bed rest patients. NASA says hospital-based deconditioning is a large problem in America, but these findings show it can be reduced with daily exercise performed in bed.
“I think there would be a lot of benefits and a lot of information that we could learn from these studies because there are a lot of people on earth who end up in bed rest, for reasons other than signing up for a research study,” said Ploutz-Snyder.
For those of us who are fortunate enough to move about the world every day, the results help to solidify what many past studies have shown: that both strength training and high intensity exercise offer many long-term health and fitness benefits, including the potential to keep us strong and healthy all through life.