As the cardio deck fills up in preparation for warmer weather, I feel that I should take the opportunity to share some ideas related to cardiovascular fitness and fat loss. We all want to look and feel our best, but sometimes we just can’t seem to find the time to stick to a plan. Although we’ve all been told, at one point or another, that slow & steady cardio is the way to drop pounds and improve aerobic capacity that may not be the end of the story. What if there was another way to lose fat, improve cardiovascular health, and save time? Let’s dig in.
Why do you do cardio, or why do you think you should do cardio?
If we asked most people this question, I would venture to guess that the majority of answers would sound something like this:
- To lose weight
- To improve cardiorespiratory health (aka: heart/lung function, aerobic capacity, VO2max, etc.)
Traditional Cardio can help you achieve both goals. Especially if someone is starting an exercise program for the first time in a few months (or longer). If you’ve just been sitting on your couch for the last few months, traditional cardio should be beneficial for weight loss and improved cardiorespiratory fitness.
Traditional Cardio = steady state, continuous exercise
- Elevated heart rate around 60-75% max heart rate, or HR around 120-150
- 30-60 minutes on a treadmill, elliptical, bike, etc.
- At this pace you could still hold a conversation
Do we really understand what those goals mean?
- Lose weight – most people do want to lose some weight, or at least maintain a healthy weight, but the focus should be on weight loss from specific tissues, namely fat stores. In reality, this goal should be “fat loss” rather than “weight loss” because we do not want to lose weight from muscle tissue (in most cases).
- Cardiorespiratory Health – the aim here is to improve the function of the heart and lungs. The heart, lungs, and blood vessels combine to form the cardiorespiratory system which delivers oxygen to working muscle tissue and removes metabolic waste. The healthier the cardiorespiratory system, the more efficient that process becomes. As cardiorespiratory fitness improves, the heart and lungs do less work when the body is at rest, and a given level of submaximal work (ex: jogging on a treadmill at 5 mph) becomes easier for the body to handle.
Is there a better way to achieve these goals?
Traditional, steady state cardio often leads to a loss of lean muscle tissue (the body doesn’t want to carry around extra muscle if you keep telling it to run multiple miles). The amount of muscle lost depends on strength training and nutrition, but ideally we want to find a method that preserves or even builds lean tissue. Sprints and intervals will not have the same catabolic (breakdown) effects on lean tissue. Depending on a person’s training age or exercise experience, these methods may even build lean tissue.
Intervals, HIIT = alternating periods of high-intensity work, followed by low intensity/recovery work
- High intensity work to elevate the heart rate past the anaerobic threshold (when muscles begin to burn), followed by slower, easier recovery work
- 30 seconds to 2 minutes of intense work, alternating with recovery work in various lengths of time (work to rest ratio may be 1:1 to 1:6)
Sprints = short bursts of all-out effort, with full or near full recovery
- Max effort work, typically only using methods that can exhaust the systems (running sprints, rowers, battle ropes, burpees, etc.)
- 10 to 30 seconds should be the limit due to the intensity of the work being performed
- Recovery may be incomplete to challenge metabolic systems, or may last a few minutes to allow for complete recovery and full intensity on consecutive sprints
Steady state cardio is not the only way to achieve cardiorespiratory health (or to challenge the oxidative/aerobic energy system). Running miles is not synonymous with cardiovascular health. Recovery between sprint bouts or high-intensity intervals relies heavily on the oxidative/aerobic energy system. During these “rest” periods, your heart rate is still elevated to the same level you would experience during steady state cardio. Sprints and HIIT will also activate fat burning better than traditional cardio.
Let’s look at a couple of studies that compare interval or sprint training to a traditional cardio protocol.
Trapp, E. G., Chisholm, D. J., Freund, J., & Boutcher, S. H. (2008). The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women. International Journal of Obesity, 32(4), 684-91.
The exercise protocols:
- HIIE (high intensity interval exercise) = 8s cycle sprint:12s slow cycling (max of 60 repeats, max of 20 minutes)
- SSE (steady state endurance) = cycle at 60% VO2peak (max 40 minutes)
This study found that both the HIIE and SSE exercise protocols increased absolute VO2peak (cardiorespiratory health) by 23.8 and 19.3%, respectively. That means the interval protocol actually did a better job than steady state cardio.
Another interesting and important difference was the time it took to complete each exercise protocol. The aerobic component of the HIIE protocol amounted to 36 minutes per week (ignoring warm-up and cooldown) compared to 120 minutes per week of aerobic component in the SSE protocol.
“Despite exercising half the time, HIIE subjects in the present study lost 11.2% of total fat mass with SSE subjects experiencing no fat loss.”
Burgomaster KA, Howarth KR, Phillips SM, et al. Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans. The Journal of Physiology. 2008;586(Pt 1):151-160.
The exercise protocols:
- SIT (sprint interval training) = 30s x 4-6 repeats, 4.5 min rest, 3x/week, all-out effort;
- ET (traditional endurance training) = 40-60 min cycling, 5x/week, 65% VO2peak
This study found that 6 weeks of sprint training led to adaptations in muscle metabolism and metabolic control that were comparable to those adaptations seen in traditional endurance training (they were equally effective at improving cardiovascular metabolism). The key, however, is that the sprint training protocol required a much lower training volume (about 90% lower) and much lower time commitment (a third of the time). Additionally, most of the time spent in the sprint training protocol was recovery between sprints – actual time exercising or running was only about 10 minutes, compared to 4.5 hours with traditional endurance training.
Hazell, TJ, et al. “Running Sprint Interval Training Induces Fat Loss in Women.” Applied Physiology, Nutrition, and Metabolism, vol. 39, no. 8, 2014., pp. 944-950doi:10.1139/apnm-2013-0503.
· SIT (sprint interval training) = four to six 30-second, all-out sprints on a self-propelled treadmill, 4 minutes of rest between sprints; 3x/week
In this study, fifteen recreationally active women completed 6 weeks of the SIT protocol. This method of training decreased body fat mass by 8.0% and waist circumference by 3.5%. SIT actually increased fat-free mass (lean muscle tissue) by 1.3%, and improved maximal oxygen consumption by 8.7% (all good things). There were no differences in food intake during this study, so all improvements were due to the exercise protocol.
A few methods to try
In addition to the methods listed above in the studies, here are a few ways you can try sprint and interval training yourself.
Running Sprints –
1. Find a distance that takes 10-15 seconds to cover with an all-out sprint (down and back on a basketball court, the straigthaway on the track)
2. Sprint that distance, then rest for the remainder of a minute (45-50 seconds)
3. At the top of the minute, start your next sprint
4. Repeat this for 5 to 10 total rounds. If you are not able to put in max effort on each sprint, feel free to increase your rest period
Rower Sprints –
1. Set the rower to count down from 30 seconds
2. Bump up the rower difficulty level to 7-10
3. Row all-out for 30 seconds, and try to get to 150m
4. Rest for 2 minutes and repeat the sprint, try to reach the same distance in each sprint
5. Repeat 5 to 10 total rounds
FreeMotion Incline Trainer (Treadmill) Intervals
1. Walk at a low incline and slow pace (2 incline/3.5 speed) for a few minutes to warm up
2. Crank up the intensity by tapping the quick change buttons on the side of the console (try incline 20/4 speed)
3. Work at a high incline for 1 minute, then walk at a normal pace and low incline for 2 minutes
4. Repeat this for a total of 6 rounds (you should be done in about 20 minutes)
You can choose from several different modalities, or methods of conditioning. One requirement you should keep in mind is that the method you choose should be able to jack up your heart rate in 30 seconds or less. If it takes you a couple of minutes to get your heart rate elevated on an elliptical, for example, then that might not be the best piece of equipment to choose for intervals or sprints. Sprints and intervals will definitely be more intense than traditional cardio, but they can be even more effective and will certainly save you time. So have fun with these new methods, but come ready to work!