Cardio 101



I've talked a lot about lifting weights and NOT doing cardio...not because I hate cardio but often because many people are doing too much cardio and too little lifting.


There are a TON of benefits for cardio. It improves your cardiovascular health, lung capacity, endurance, conditioning and more.


In the realm of nutrition, cardio is most often used as a weight loss tool.


Cardio use is a tool that we use in almost every cut, diet, and fat loss phase (all terms used interchangeably).


But it’s just that…a tool. It’s by no means a requirement. In fact, most often we start first with food to create the first deficit.


When you start a cut or diet to lose weight, you first want the deficit to be created by food. However, at some point during your diet phase you will likely need to increase that deficit, meaning burning even fewer calories than you’re expending. This is usually because at some point during your 8-12 week cut, your weight loss is going to plateau. At this point, you could create a further deficit by taking away more food. If I have someone who just started a cut or has been cutting less than 6 weeks, this is usually my first plateau-breaking strategy. However, let’s say you’re pretty steep in that deficit or adherence is already a bit questionable or you’ve been cutting for more than 6 weeks, taking away food may not be the best option for you. In these cases, we will increase your activity by implementing cardio, which will increase your caloric expenditure. While keeping intake the same, this will create a larger deficit allowing you to resume a steady rate of weight loss.


There are three types of cardio you can implement: light, moderate, and vigorous cardio. The difference is based on the perceived exertion you experience.


To decide which cardio to implement, there are a couple things to consider.


The first thing to consider is how much of a deficit you need to create…also how much more energy you need to expend to make the cardio use result in weight loss. A pound of fat/adipose tissue equates to roughly 3500 calories. To lose a pound of fat, you’d need to be in a deficit of 3500 calories/week. If you divide that by 7 (7 days/wk), then you’re dropping 500 cals/day to lose 1lb/week. Generally in a cut, you’re aiming to lose 0.5-1% of bodyweight/week. A 150lb individual would aim for rate of 0.75-1.5 lb/week, probably on the 0.75lb/week side as they likely don’t have as much weight to lose as say a 250lb individual wanting to drop 50-75lbs.


*This isn’t exact, but it gives us the best estimation. The rest is done empirically by HOW your body responds*


Second thing to consider is how much calories are being expending per session of cardio. We do this using an RPE Scale (rate of perceived exertion). This is simply done by assessing how hard your cardio/effort feels on a scale of 1-10. See chart below.

Knowing your body weight, the time spent performing cardio, and the intensity (RPE) of cardio, you can determine your caloric expenditure. You burn approximately 0.2, 0.45, and 0.7 kcal per 10 minutes per lb. of body weight doing light (RPE 2-4), moderate (RPE 5-7), and vigorous/intense (RPE 8-10) cardio respectively. Now…that’s a lot of math. Below is a chart for 3 common body weights relative to the type of cardio.

Example. A 160lb individual doing moderately intense cardio for 10 minutes would burn ~72kcals (160x0.45). If they performed the same cardio for an hour, they would burn ~432 kcals (72 kcalsx6) over what they expend on a normal day with normal activity.


Great…SO I’m just going to do a ton of cardio (160lb. individual = 2.5 hrs/day light or 1hr/day moderate intensity or 50min/day high intensity) and keep my food the same. That works, right?

Mathematically, yes. Unfortunately the realistic answer is a firm no. 7-9 hours of cardio per week is going to pose some problems for anyone wanting to maintain body composition and build muscle. That much cardio is going to likely create too much inflammation. You’re implementing this cardio in addition to your daily lifting routine. 1. How are you going to find an extra 1-2 hours/day to add in cardio and 2. How are you going to find the energy? That much additional cardio is going to create a ton of inflammation and likely lead to adaptations as well.


That’s why we most often implement cardio as a supplemental tool.


The third, and final thought to consider in implementing cardio is the type of cardio. What type of exercise? Light? Moderate? Or High? Does it matter whether you’re running, biking, swimming?


Moderately intense cardio is essentially endurance training. The work required to produce endurance changes in your body can interfere with the training and adaptations that come from weight training, building muscle, hypertrophy, and power. Often the impact from moderate intense exercises interferes as well. Excessive amounts of this type of cardio will greatly reduce the ability to build muscle and may likely lead to a loss of muscle during a deficit. You want to limit moderate intense exercise to 1-2 hours/week and keep impact minimal by choosing non-impact modalities such as rowing, biking, swimming, and the elliptical. High impact modalities create joint strain and put the muscles under more fatigue which will likely affect your weight training.


Low intensity cardio does not have the interference or adaptations that come from moderate intensity cardio, especially if non-impact. It doesn’t overload the muscles or joints because of the reduced effort and lack of adaptive stress. Unfortunately, in most cases (except CrossFitters, see in a bit), low intensity cardio takes significantly more time to create the deficit needed because the calorie burn is so much lower. However, in the case of CrossFitters, one of the best benefits of low-intensity is the recovery component. If you are a CrossFitter, majority of your cardio should come from low intensity cardio because you’re already in a pretty high impact sport and performing already a ton of high intensity work. Adding more will create more strain and make you more prone to injury. What you need is recovery, and this will kill two birds with one stone!


The last option is high intensity cardio, most often seen as HIIT (or high-intensity interval training). High intensity cardio is incredibly taxing. You’re in the RPE ranges of 8-10. This is a lot of sprint work. Because of the increased intensity, you’re not able to sustain it very long, which is why we see it most often in interval-style. This could look like 15s of an all-out 110% effort, followed by 60s low, recovery 25-35% effort repeated 5-10 times. Because you’re going in short bursts, this mimics the training and adaptations of lifting and resistance training, so the interference in training adaptations is pretty minimal. The downside of HIIT or any high intensity cardio is the degree of stress and greater need for recovery. It is very high impact which creates a TON of stress and can lead to risk of injury. Sprinters have a much higher chance of injury as compared to an endurance athlete or mom-walker. If you are a high stressed individual or high competitive CrossFit athlete, this shouldn’t be utilized as much unless you’re willing to take the extra means of recovery.


As you’re probably figuring out, there isn’t one cardio that’s perfect. The best prescription is going to be a combination of all of the types of exercise. The one exception is going to be our CrossFitters, who are going to benefit mostly from low intensity exercise. You’re a strength trainer…not an endurance athlete so don’t throw the weights away during your cut.


This is also why the majority of your deficit should be coming from your diet and why you should still be resistance training during your cut. These two are going to create the body comp changes you’re looking for, while keeping your body healthy and happy. The diet is going to help create the fat loss and the resistance training is going to retain your muscle. The cardio is simply a tool to help you down the road if or when you plateau. This is also why it’s SO crucial that you’re not doing excessive amounts of cardio to start or during maintenance. If you’re already doing a ton to start, there’s not much you can add to create more of a deficit. Instead, you’re going to have to solely rely on taking food away, and that can get pretty miserable.


Generally, you want to be adding in cardio that takes no more than half the time you spend lifting. If you lift 1.5 hours/day for 5 days/week, that’s 7.5 hours of weight training. You should implement no more than 3-4 hours/week of cardio, and I wouldn’t start at 4 hours. I’d start at 2 and see if your weight starts dropping at the appropriate rate. You want to find the minimal effective dose! Then if you plateau again, you have another 2 hours of cardio to tack on.


Choose cardio that is easy on the joints and low impact (elliptical, biking, rowing, swimming). Do no more than 1-2 HIIT sessions (capped at 30 minutes at most) and 1 hour of moderate exercise per week. Fill the rest in with low-intensity cardio.


Taking the example above, 4 hours of cardio could look like 2 30-min HIIT finishers (done on training days), 1 hour moderate intensity exercise (either 4 hours out of training window or on rest day), and 2 hours of low-intensity cardio thrown in throughout the week (20 min walk daily, 2x 1 hour walks on rest days, or 4x30 min walks). If you started small with 2 hours, this could look like 1 HIIT finisher, 30 min moderate intensity, and 1 hour of low intensity cardio per week.


Pro-tip…If you can, do your cardio outside in the sun and soak up some Vitamin D!


This is one of the many benefits that comes from hiring a coach. As a coach, I do all of this hard work for you so you don’t have to worry about the stress of implementing it on your own. If you’re tired of doing it all on your own and want the education, individualization, and ease of mind, sign up today for a free consultation call.

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