Few things in the realm of training are black and white, even those things that are regularly talked about in very black-and-white terms. A prime example is rest, particularly when it concerns fat burning. Talk to 100 run-of-the-mill personal trainers about the topic and 90-something of them will say essentially this: To lose fat, rest periods need to be short, if not nonexistent, and rest days should be few and far between.
These statements are true … except when they’re not. Burning fat can’t be summed up in a single sentence because, you guessed it, it’s not always black and white. Maximizing fat loss requires some critical thinking, an understanding of the body’s physiology, common sense and, perhaps most important, years of trial and error.
To address the topic of rest and fat burning, we’ve selected someone who possesses all of these requirements: Tom Seabourne, Ph.D., CSCS, professor of exercise science at Northeast Texas Community College (Mount Pleasant), author of 16 published fitness-related books and a world-record-holding ultra-distance cyclist who has cycled more than 1 million miles all while maintaining a muscular physique. If Seabourne doesn’t know fat burning, nobody does.
Rest Between Sets
We can all agree that resting five minutes between sets is not the best way to torch body fat; such long rest periods virtually eliminate intensity. But so, too, does not resting at all, which explains why high-intensity interval training — where rest periods or active-recovery intervals are prescribed — is now known to be considerably more effective at burning body fat than steady-state cardio (where, by definition, you don’t rest).
When it comes to resistance training, intensity is once again a key factor. However, hypertrophy (muscle building) also matters greatly. When approaching your weight-training sessions, you shouldn’t be deciding between muscle growth or fat burning; rather, you should be seeking hypertrophy as a means of maximizing fat loss. Muscle tissue is highly metabolic, so the more of it that you have, the more fat you’ll burn.
“You’ve decreased the amount of rest between sets, great, but if that diminishes the amount of weight you’re able to use, then you’re not going to build as much muscle and therefore your metabolic rate is not going to increase as much,” Seabourne notes. “So there’s that fine line. You want to have enough rest between sets to be able to lift maximum weight, but not so much that your heart rate comes back down close to resting.”
Full rest periods for someone training in the eight- to 15-rep range would likely fall between one and three minutes. To emphasize fat burning, however, the goal would be to slash those rest periods while not having to drop weight considerably. This is where trial and error comes into play.
“If your primary goal is fat burning, then you’re on that tightrope where you say, ‘Okay, yesterday I did 70 to 80 percent of my one-rep max [1RM] for 10 reps or so and 45 seconds rest between sets. Let me see if today I can do that same weight with 30 seconds rest and the same number of reps or very close to it.’ So over time you’re constantly trying to minimize the rest but maximize the weight,” says Seabourne.
Keeping rest periods brief while training loads remain high is easier said than done. It can take many months to build up muscle endurance and condition your body to withstand such high intensity. In the short term, circuit training and supersets can help because they give muscles a chance to recover locally between exercises.
“Circuit training and supersetting allow you to go from exercise to exercise with basically zero rest,” Seabourne explains. “Research talks about using 60 percent of your 1RM when doing circuit training, but that’s for the average individual. An advanced lifter could work up to as high as 80 to 90 percent of 1RM with literally no rest, especially if doing supersets where opposite muscles are being worked.”
Rest Between Workouts
The philosophy that more training translates to more calories and fat being burned works for some, but not all. Remember, hypertrophy fosters fat loss, and your muscles won’t grow if they aren’t allowed adequate rest and recovery. Anything that takes away from growth — such as lifting seven days a week and being overtrained — won’t be good for fat burning.
“In my opinion, everybody’s going to be different in terms of how much rest they need between workouts,” says Seabourne. “The research talks about working each muscle group twice a week to promote growth. You have to listen to your body, since we all have different recovery times.”