There is so much confusion out there about how much cardio you should do to lose weight. Some say you need to be doing it every single day. Some say twice a day, and some even say you don’t have to do it at all. So then, who’s right? Let’s break it down and see if we can clarify the question.
How Much is REQUIRED to Lose Weight?
Short answer – absolutely none. Am I recommending that you do zero cardio to lose weight? Absolutely not. However, from a strictly physiological standpoint, cardiovascular training is not required at all to lose weight. Don’t think so? Try not eating anything for a week while you are completely sedentary. Obviously, in time, you will wilt to nothing.
As health and fitness individuals we aren’t just trying to lose weight. We are trying to spare muscle tissue (or build some) while we drop our body fat. Sometimes that means we lose weight, but sometimes that means our weight stays the same while our body composition changes. The only way to know what’s really going on is to measure with body fat calipers. Either way, the question shouldn’t be how much cardio to lose weight, but instead – how much cardio to lose fat?
How Much Cardio to Lose Weight (Fat)?
Strictly speaking, as with all things fitness related, it’s going to depend. However, there are a few guidelines I like to follow that I think are good catch-alls for most people.
- If you have a sedentary job, it’s a good idea to do cardio.
- If your strength training workouts aren’t high intensity, it’s a good idea to do cardio.
- If reaching your desired goal means you have to eat below your BMR, it’s a good idea to do cardio.
In other words, if all you do is work out for 30 minutes and then sit behind a desk at your job, you’re going to want to get more active. Remember, part of living a health and fitness lifestyle means being active. Get up and move around. I personally use my BodyMedia FIT Armband and try to hit a step number every day (10,000). Before I wore the armband, I was only getting in around 5,000 steps at the most each day, and that included my workouts. Since I’m behind this computer most of the day, my wife and I added in short walks at night just to get in a little extra activity. Every little bit helps.
The same goes for if your strength training workouts aren’t that intense. Most people forget that strength training and cardio don’t have to be two separate, mutually exclusive activities. Cardio is short for cardiovascular training. If you are pushing yourself hard during your workouts, additional cardio like running or biking is not always necessary. My weight training days are very strength-based, so I don’t get as much cardiovascular training as I’d like. Because of this, I throw in some sprint work between sets or some form of agility training, like the agility ladder.
Finally, if hitting your weight loss goal of say 2 pounds/week means that you would need to eat below your BMR, you should instead eat more food and do additional cardio work (eat more, move more). Let’s take a look at my go-to equation (The Katch-McArdle Formula) for determining an accurate BMR:
BMR = 370 + (21.6 * LBM)
LBM is your lean body mass in kg. I like this equation because most others don’t take into account body composition. As muscle is more metabolically active than fat, I believe this formula is much more accurate. So, let’s break down an example for someone who is 150lbs at 20% body fat. Someone at those stats has 30lbs of fat (150lbs * 20%bf = 30lbs). Subtract those 30lbs from their weight, and you get 150lbs – 30lbs = 120lbs of lean body mass.
Next, take that number and convert it to kg. So 120lbs / 2.2 = 55kg of lean body mass. Now we just plug those numbers into the Katch-McArdle formula above:
BMR = 370 + (21.6 * 55) = 1558 calories
If reaching your weight loss goal means you have to eat less than 1558 calories to maintain your weight loss pace, it’s a much better idea to at least eat your BMR and create your deficit with additional cardio. Eating below your BMR is a sure way to lose muscle and stall your weight loss.
Determining Your Cardio Requirements
Now that you know if you should be doing cardio or not, let’s briefly cover how much cardio you should do to lose weight. I recommend that you do the least amount that is necessary to reach both your exercise goals AND your body composition goals. If you have goals to improve your cardiovascular fitness, or to have a faster 5k time, your training is going to need to reflect that. If you’re just trying to maintain your cardiovascular fitness while dropping body fat, you won’t need as much. Whatever your goals, be efficient with it. The reasons are several-fold:
- In a hypo-caloric environment it is much easier to over-train.
- The few calories and nutrients you’re ingesting are needed to support muscle tissue growth and repair. Devoting unneeded energy to cardio works against those goals.
- It is much easier to cut 100 calories from your diet (if you have room to – remember, don’t eat below your BMR) than it is to add in 100 calories worth of exercise.
Whether you need an additional 100 calories, 300 calories, 500 calories or more worth of cardio calories depends on the factors outlined above. Whatever amount you choose to do, just make sure cardio is working for you and not against you.