A while back, one of my Facebook followers asked an interesting question pertaining to the role of cardiovascular (cardio) exercise in weight loss:
“Dr. Nina, I would like your take on the idea of eliminating intense cardio exercises like running for weight loss…Is there any empirical data that supports or denies this claim?”
Believe it or not, this is actually an ongoing debate, both inside and outside the scientific community.
Let me first start by saying this: There’s absolutely NO need to eliminate cardio exercise if you’re trying to lose weight. When it comes to cardio, the issue isn’t necessarily the time spent exercising but rather the intensity at which you work out.
Exercise intensity is inversely related to duration (time). This essentially means that any exercises performed at a higher intensity (high-speed running) should be performed for shorter periods of time while low-to-moderate intensities of exercise (walking) can be performed for longer periods of time.
Excessive amounts of high-intensity exercise can lead to what’s called oxidative stress. Regular exposure to oxidative stress can impair blood vessel function, which actually increases the risk of chronic disease, namely heart disease. This is why we as exercise scientists don’t recommend prolonged exposure to high-intensity exercise bouts.
Now, this is not to say that you can’t participate in occasional marathons for the love of running. But, constantly running in marathons for the sake of losing weight may in fact present an issue.
If you prefer to engage in high-intensity exercise for the love of it, there’s no need to fret. Just alternate your high-intensity workouts with those that are of a low-to-moderate-intensity. Still, I’ll emphasize again that it’s not wise to perform excessive amounts of cardio exercise of any kind for weight loss, especially at high intensities.
Personally, I can put in well over 7-10 hours of cardio each week in the forms of running, stair climbing, and cycling.
But, not for weight loss.
This is therapy for me and I’m physically trained to do so.
I also make an effort to regularly switch up the time, type and/or intensity of my cardio routine as opposed to doing the same thing every day. In addition, every hour of cardio I put in is matched with an hour of resistance (weight) training.
And, this brings me to my next point.
If you regularly follow my blog or social media channels, you’ll notice a bias towards weight training.
I’m biased for a reason.
I’m a huge advocate of this type of training for weight loss — Even more so than cardio.
Training this way not only preserves muscle, but it also fuels the fat burning process that’s necessary for successful and sustained weight management. Without such training, your cardio is essentially performed in vain.
Unfortunately, many folks spend hours and hours performing cardio exercise for the sole purpose of losing weight and rarely, if ever, touch weights out of a fear of “bulking up”.
When excessive amounts of cardio are performed for weight loss, muscle is inevitably lost. This holds especially true when you don’t regularly engage in moderate-to-high-intensity weight training. Losses in muscle are even greater if you also restrict calories while doing so.
This is one of the reasons why people who lose weight in the absence of resistance exercise tend to look “fatter”.
So, what’s the net-net?
Well, the science definitely supports the notion of regular exercise training for weight loss, long-term weight management, and overall good health. This includes both cardio exercise and weight training.
Both are uniquely beneficial.
For maximal benefits, your cardio routine should include a combination of low-, moderate-, and high-intensity exercises performed for no more than 90 minutes each day (depending on the intensity). Again, lower intensities of exercise (walking, leisure biking or swimming) can be performed for longer periods of time.
And when it comes to weight training, you should perform at 8-10 exercises targeting all your major muscle groups with resistance that’s sufficient enough to fatigue them within a maximum range of 8-15 repetitions. This is especially important, as many people simply don’t use enough resistance to achieve significant results.
I’ve written extensively on the importance of resistance training for weight loss. In most cases, this type of training can negate any potentially negative effects of cardio, which is why it’s recommended.