New research suggests hybrid exercise cuts heart disease risks

CardioRACE trial investigates cardiovascular risks in overweight adults.


New research from Iowa State University shows that splitting exercise between aerobic and resistance training, especially for higher weight individuals, can reduce cardiovascular disease risks as effectively as solely focusing on aerobic exercise. 

This discovery comes from one of the longest and largest supervised exercise trials, addressing the lack of studies comparing different workout regimens. The study, published in the European Heart Journal, highlights the significance of incorporating both aerobic and resistance exercises for optimal heart health benefits, emphasizing their effectiveness in lowering cardiovascular risks compared to aerobic-only or resistance-only approaches.

Duck-chul Lee, lead author and professor of kinesiology at Iowa State, said, “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 other unique health benefits, like improving your muscles.”

Resistance exercise involves sets and repetitions using weight machines, free weights, or body weights. Combining cardio and strength training, suggested by researchers at Iowa State University, proves effective and time-efficient. Limited time is a common barrier to exercise, and the proposed approach addresses this concern. 

The study’s co-authors emphasize the potential impact on the approximately 2 billion higher weight or obese adults globally, stating that the findings may shape clinical and public health recommendations for reducing cardiovascular disease risks.

In a year-long exercise trial involving 406 participants aged 35-70 with higher weight or obesity and elevated blood pressure, researchers at Iowa State University explored the impact of different exercise regimens. Divided into four groups – no exercise, aerobic only, resistance only, or combined aerobic and resistance – participants in the exercise groups had supervised sessions for one hour, three times a week. 

Tailored routines were provided based on individual fitness levels. Resistance training involved specific sets, repetitions, and weights, while aerobic exercises utilized heart rate monitors and custom exercise programs on treadmills or stationary bikes, automatically adjusting intensity based on heart rate.

Researchers gathered data on physical activity and diet outside the lab in a year-long trial. All participants wore pedometers to track daily steps, even in the no-exercise group. Every three months, they had dietary education sessions. Additionally, participants recorded their daily food intake on three random days monthly. 

The researchers assessed systolic blood pressure, LDL cholesterol, fasting glucose, and body fat percentage at the start, six months in, and at the trial’s end. By combining these factors into a composite score, the study aimed to quantifiably measure changes, providing a comprehensive view of cardiovascular disease risk reduction.

In the year-long trial’s main findings, all exercise groups showed a significant decrease in body fat compared to the no-exercise group. A 1% reduction in body fat was associated with lower risks of hypertension, hypercholesterolemia, and metabolic syndrome. Considering all four cardiovascular risk factors, the aerobic and combined exercise groups had lower composite scores than the control group, with consistent results across gender and age. 

In secondary findings, the aerobic-only group improved in VO2 max, measuring oxygen consumption, while the resistance-only group improved in muscular strength tests. The combination exercise group saw improvements in both aerobic fitness and muscular strength.

The study supports existing physical activity guidelines recommending aerobic and resistance exercise for individuals with obesity. While guidelines prescribe 150 minutes of moderate aerobic exercise weekly and two resistance sessions, they lack details on the ideal duration for strength training. 

With a new grant, Lee aims to determine the optimal resistance exercise dose for higher weight or obese adults. A randomized controlled trial with 240 participants will compare 0-, 15-, 30-, and 60-minute resistance sessions, combined with aerobic exercise, over six months. The study aims to identify a practical and feasible duration for resistance exercise for real-world applications.

Journal reference:

  1. Duck-chul Lee, Angelique G Brellenthin et al., Aerobic, resistance, or combined exercise training and cardiovascular risk profile in overweight or obese adults: the CardioRACE trial. European Heart Journal. DOI: 10.1093/eurheartj/ehad827.


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