One of the longest and largest exercise trials
The researchers from Iowa State University included 406 overweight or obese participants (35-70 years of age) with elevated blood pressure in a 1 year-long randomised controlled exercise trial. The participants were split into four groups.
No exercise: These participants didn’t exercise and served as a control group
Resistance only: 1-hour resistance training session on weight-lifting machines, 3x per week
Aerobic only: 1-hour aerobic intensity session on a treadmill or stationary bike, 3x per week
Combined exercise: 1-hour split into half resistance and half aerobic training, 3x per week
The resistance group was prescribed 3 sets of 8–16 repetitions at 50%–80% of one-rep max on 12 weight-lifting machines (leg press, hamstring curl, quadriceps extension, hip abduction, chest press, lat pulldown, shoulder press, biceps curl, triceps extension, abdominal crunch, lower back extension, and torso rotation) with 1 min of rest between. The aerobic group was prescribed exercise at 50%–80% of their heart rate reserve, calculated as [(maximum heart rate − resting heart rate) × %intensity] + resting heart rate, using treadmills, stationary bicycles, and elliptical machines.
The researchers also collected physical activity and diet data outside the lab during the trial. All participants, including those in the no-exercise group, wore pedometers to measure daily steps. They met every 3 months with registered dietitians for “Dietary Approaches to Stop Hypertension” education. They were also asked to record what they had consumed with an online dietary assessment tool.
Aerobic and combined exercise are best for cardiovascular health
At the start, at 6 months, and at the end of the trial, the researchers measured each participant’s blood pressure, LDL cholesterol, fasting glucose and body fat percentage to assess their cardiovascular disease risk. Here is what they found.
Body fat percentage dropped significantly for all three exercise groups but not for the control group.
Blood pressure was reduced in all groups over the course of the trial but the aerobic and combined groups reduced it by 3x and 4x, respectively, as much as the control or resistance group.
LDL cholesterol increased in the control group, reduced slightly for the resistance group, and dropped significantly for both aerobic and combined groups.
The overall cardiovascular disease risk was significantly reduced for the aerobic and combined groups, only slightly for the resistance group and almost not at all for the control group.
“If you’re bored with aerobic exercise and want variety or you have joint pain that makes running long distances difficult, our study shows you can replace half of your aerobic workout with strength training to get the same cardiovascular benefits. The combined workout also offers some other unique health benefits, like improving your muscles,” says Duck-chul Lee, lead author and professor of kinesiology at Iowa State University.
