If you wear a heart-rate monitor, you may notice that it's more challenging to hit high numbers when cycling versus when running. You aren't alone. In general, running causes your heart rate to soar more than cycling at both maximal and submaximal levels. The difference in heart rate during each sport has an impact in how you use your heart-rate monitor to help you improve performance in each discipline.
A study in a 2009 issue of the "Journal of Strength and Conditioning Research" found that triathletes reached their lactate threshold at a heart rate about 12 beats lower during cycling than during running. Lactate threshold is the point at which the body can no longer process lactic acid, produced by exercise, at the rate at which it's being produced. The accumulation of lactic acid in the muscles causes you to slow down as your muscles fatigue.
A paper in the 2009 issue of “Sports Medicine” notes that differences in your heart-rate training zones in running versus cycling may not be as dramatic if you are more proficient at one specific sport. For example, dominant cyclists can raise their heart rate to nearly the same point that they can on a treadmill, but runners cannot always get to the same threshold on the bike as they can when running. Researchers aren’t sure why this is true, but surmise that they may have muscle and cardiac adaptations that occur with training.
If you're an athlete who uses training that involves intervals at or near lactate threshold, you may have to adjust your expectations when moving from cycling to running. If you have access to a facility that offers testing to determine your heart-rate max and participate in both cycling and running, you should have separate tests done for each mode of exercise, concluded a study published in a 2003 issue of the “International Journal of Sports Medicine.” Your heart-rate zones will differ for each sport and thus you can train more specifically to improve your performance. You may also learn to rely less on the numbers exhibited by your heart-rate monitor when exercising and more on your perceived exertion levels to tell you when you're reaching your lactate threshold.
Using a heart-rate monitor can be a useful strategy in improving your performance at cycling and running, but it isn’t the only one. As you become more attuned to your body, you may learn to rely less on the numbers exhibited by your heart-rate monitor when exercising and more on your perceived exertion levels to tell you when you're reaching your lactate threshold. Perception of effort is probably a better tool to use to gauge desired pace during racing, for example. If you rely on heart-rate numbers, you may unnecessarily limit your performance.
- International Journal of Sports Medicine: Heart-Rate Recommendations: Transfer Between Running and Cycling Exercise
- Sports Medicine: Physiological Differences Between Cycling and Running: Lessons From Triathletes
- Journal of Strength and Conditioning Research: Transferability of Running and Cycling Training Zones in Triathletes: Implications for Steady-State Exercise
- Velo News: Training Center: Are Heart Monitors Still Useful for Cycling?
- Bicycling: Don't Trust Your Heart
- Comstock/Comstock/Getty Images