Chances are, you probably do some form of cardiovascular exercise. When you first started working out, you might have eagerly anticipated shedding a few pounds of body fat from cardio alone. You might have even experienced some weight loss initially but either quickly regained it or hit a plateau where the fat loss stopped. After getting over your disappointment, you might have wondered why. In reality, this is a fairly common experience. For most people, cardiovascular exercise alone isn’t highly effective for fat loss.
Of course, this doesn’t mean that cardiovascular training doesn’t have health benefits. It does. In fact, cardiovascular workouts are linked with a laundry list of mental and physical health benefits. A heart-pumping cardiovascular exercise session improves insulin sensitivity and blood sugar control. It also helps lower blood pressure, has favorable effects on blood lipids, boosts stamina and endurance. An energetic bout of cardio positively impacts other organs as well, particularly your brain. For example, we know that aerobic exercise improves mood and lowers the risk of depression. Plus, it helps preserve cognitive function as we age. There’s also ample evidence that regular cardiovascular training helps slow loss of brain volume in an area of the brain called the hippocampus. That’s important since your hippocampus is involved in memory.
So, don’t downplay cardiovascular exercise even if you question whether it’s a good standalone strategy for weight loss. What’s more, some studies DO suggest that cardiovascular training IS effective for weight loss. The problem is not all research that shows benefits distinguishes between weight loss and fat loss. For example, a study published on Science Daily found that participants who did aerobic exercise lost weight, almost 4 pounds after 8 months of training, while a group that did resistance training lost no weight. Yet, some of the weight loss in the aerobic training group was muscle. We don’t want that!
Wouldn’t a combination approach be better – aerobic exercise plus resistance training? The combo should lead to greater loss of body fat while preserving lean muscle – and it’s certainly more sustainable than doing hours of monotonous cardiovascular exercise. Plus, doing both forms of training reduces the boredom factor.
Why Cardiovascular Exercise Doesn’t Always Lead to Fat Loss
As you can see, there is evidence that cardiovascular exercise helps with weight loss but some of the weight loss will likely be muscle and that won’t improve your body composition. Yet, there are people who experience little or no loss of weight despite doing thirty or more minutes of cardio daily. Why might this be?
For one, we often overestimate how many calories we burn during a cardio workout. If you weigh 150 pounds and take a 30-minute moderate-intensity jog, you’ll burn just under 300 calories. That might sound like a lot until you think about how easy it is to knock down 300 calories. A single breakfast muffin has more than that. Plus, we often feel entitled to eat a bit more on days that we exercise. It’s easy to compensate and overcompensate for the calories you burned during cardiovascular exercise.
What about its impact on appetite? Does aerobic exercise actually make you hungrier and cause you to eat more? Contrary to popular belief, there’s not a lot of evidence that it does. In fact, one study found that a 60-minute aerobic workout on a treadmill altered appetite hormones, peptide YY, and ghrelin, in a way that helped with appetite suppression during and immediately after the workout. In this study, aerobic training suppressed appetite more than resistance training.
Another study found that women who engaged in a 45-minute run that looked at food photos afterward felt less hungry than on days that they rested. But, even if cardiovascular exercise doesn’t boost your appetite, you may still unconsciously reward yourself for exercising by eating more because you feel justified in doing so. We’re not always logical and don’t always eat only when we’re hungry.
Another problem: We tend to adapt quickly to moderate-intensity cardiovascular exercise. For example, when you first start doing aerobic workouts, like running, you may lose weight initially but quickly reach a plateau. Not surprising! When you run, you do the same repetitive motions over and over and your body becomes more efficient at doing them. Increased efficiency means less energy expenditure to complete that task. So, unless you vary your training, you burn fewer calories doing the same workout as your body becomes accustomed to doing it.
All in all, exercise accounts for only a small portion of daily energy expenditure, usually between 10 and 30%, but 30% would be at the level of a professional athlete. So, exercise alone isn’t a highly effective tool for weight loss, regardless of type and this is supported by a number of studies.
What IS the Best Approach?
If you can’t count on cardiovascular exercise to keep the weight off, what should you do? A combination of cardio and weight training works best. In fact, focusing your efforts more on strength training will pay off bigger dividends in the long run as it improves your body composition and the shape of your body. Plus, you build more metabolically active muscle tissue. For fat loss, focus on improving the quality of your diet. It’s an overused cliché but 80 to 90% of what you weigh is determined by how and what you eat. You simply can’t out exercise a bad diet and you’re run yourself ragged trying to do it.
Too often, we adopt the mindset that burning more calories is the key to losing weight, but this quickly becomes a time-consuming endeavor when you consider how long you have to work out to burn enough calories to lose even a half-pound. The fatigue factor quickly slips in and your cortisol level rises from training too much. This leads to loss of muscle tissue and sabotages efforts to improve your body composition. It’s a path you don’t want to go down.
Mind Your Nutrition
If you’re not losing body fat, get back to basics and look at your diet. Exercise improves your health and overall body composition, but it works best when you’re minding what you eat. Keep a food journal for a few weeks and make sure you’re eating an unprocessed diet and aren’t overdoing the volume of food you eat.
BMC Public Health. 2012; 12: 704. Published online 2012 Aug 28. doi: 10.1186/1471-2458-12-704.
Precision Nutrition. “Cardio vs. Weights: Which Is Better for Fat Loss?
Science Daily. “Aerobic exercise trumps resistance training for weight and fat loss”
Science Daily. “Exercise Suppresses Appetite By Affecting Appetite Hormones”
Sharecare. “Will cardiovascular exercise increase my appetite?”
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