A new study published in the Journal of Exercise Science & Fitness suggests that the order in which one performs workouts affects fat loss. The findings align with broader research on exercise sequencing and its impact on body composition.
In the study, researchers gathered 45 young men aged 18 to 30 who were classified as obese. These participants were divided into three groups for 12 weeks. One group served as a control and maintained their usual lifestyle habits without changing their exercise routine.
The other two groups trained for 60 minutes, three times a week. Both exercise groups followed identical training programs, differing only in the order of exercises. One group performed weight training before cardio, while the other did cardio before weight training. The participants received sports watches for objective monitoring of daily movement, which helped researchers avoid reliance on often inaccurate personal reports, as highlighted by Science Alert.
The strength training sessions included exercises like bench presses, deadlifts, bicep curls, and squats, using real weights. The cardio sessions consisted of 30 minutes on a stationary bike. Participants in both exercise groups showed improvements in cardiorespiratory endurance, cardiovascular fitness, muscular strength, and body composition.
However, differences emerged in fat loss and muscular performance based on the exercise sequence. Participants who lifted weights first experienced greater reductions in overall body fat. They also lost more visceral fat, the type linked to cardiovascular disease risk.
The group that did weight training before cardio became more physically active throughout the day. They increased their daily step count by approximately 3,500 steps, compared to the cardio-first group, which increased their step count by about 1,600 steps. This finding was reported by Science Alert.
The reason behind these findings relates to how the body uses energy, particularly glycogen stores. Resistance training depletes muscle glycogen stores, which act as the body's quick-access fuel. When lifting weights first, participants deplete their glycogen stores, forcing the body to switch energy sources, explains Science Alert. This metabolic shift helps explain the greater fat loss observed in the group that started with weight training.
Fitness enthusiasts have debated for decades whether it's better to do cardio before or after lifting weights. Until recently, the answer depended largely on personal preference. Some people enjoy jogging to warm up before lifting weights, while others prefer running afterward. However, evidence strongly supports that starting with weight training is better for burning fat. Participants who did weight training before cardio lost more fat compared to those who did cardio first.
Both exercise groups showed similar improvements in cardiorespiratory endurance and gains in cardiovascular fitness, regardless of exercise order. If cardiovascular fitness is the primary goal, the sequence of exercises matters less, as both sequences equally boost aerobic fitness. However, if the focus is on fat loss and optimization of daily activity, the evidence supports starting with weight training.
Performing cardio first might compromise the effectiveness of weight training. Cardio depletes glycogen reserves, leaving muscles partially exhausted before starting to lift weights. “Cardio induces fatigue and may reduce the muscles' ability to generate strength and explosive power,” reports Science Alert. A recent systematic review on concurrent training corroborates that explosive strength gains might diminish if aerobic and strength training occur in the same session, especially if cardio is performed first.
The study had limitations; it involved only obese young men and did not account for nutritional intake, sleep patterns, or stress levels, all of which can influence body composition outcomes. The 12-week duration may also not capture long-term changes. As such, future research should incorporate these factors for more comprehensive guidance.
Nevertheless, the findings align with other research on concurrent training. A systematic review and meta-analysis found that resistance-first protocols produced superior strength improvements compared to endurance-first training. The American Heart Association's 2023 statement on resistance training confirmed that resistance exercise improves lean body mass and reduces fat, especially when combined with other exercise types.
Both cardio and weight training improve overall health, reinforcing the importance of including both in an exercise routine. “Regardless of whether one prefers to do cardio before or after weight training, the message is clear: both improve overall health,” states O Globo. However, if the focus is on fat loss and optimization of daily activity, the evidence strongly supports starting with weight training.
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