Jogging is a great way to escape the comforts and confines of ordinary life, especially indoor-dominant home and work routines. It feels great to lace up your shoes, take off down the road, get a good sweat going, and bask in the endorphins afterward. Here’s the problem: For all but the leanest, fittest athletes, jogging is far too stressful to deliver the promised benefits of losing excess body fat and improving general health, preventing disease, and promoting longevity. For most, jogging–even at a seemingly comfortable pace–emphasizes sugar burning instead of fat burning, generates excessive impact trauma, and leads to energy lulls and increased appetite in the hours afterward. Engaging in such a pattern of workouts that are slightly-to-significantly too stressful can often result in breakdown, burnout, illness, and injury.
How can you tell if your workout pace is too stressful? Well, you could get precise by monitoring your heart rate at every workout, and you could also add an intuitive component to help guide your workout decisions. After a steady-state cardiovascular training session, you should feel more alert, refreshed, and energized than when you started. You should feel a slight elevation in mood and a small sense of satisfaction. Contrast this with the drug-like endorphin high you experience for a few hours after a really strenuous workout or race. Your muscles should not feel stiff or aching, and you should not feel depleted and hungry for a pint of Ben & Jerry’s.
That washed out feeling after workouts suggests that you have overstressed the body and emphasized sugar burning. Your body will compensate after such sessions by being lazier throughout the day, having an increased appetite for quick energy carbs, and also taking longer to recover before your next session. A pattern of workouts that are slightly-to-significantly too stressful can lead to serious problems with hormonal, immune, and metabolic function. This is known as “chronic cardio,” where you layer an overly stressful workout pattern atop a hectic, high-stress day to day lifestyle pattern.
The cutoff point between the two is your “fat max” heart rate. Also called “aerobic max”, “aerobic threshold”, or “MAF (maximum aerobic function)” heart rate, or “ventilatory threshold 1” heart rate, it represents the intensity level (measured in beats per minute) where you are burning the maximum amount of fat calories per minute with a minimum amount of anaerobic stimulation. If you were to speed up beyond fat max, you would burn more calories of course, but you would start burning fewer fat calories and more glucose calories. You would drift from an aerobic workout into anaerobic heart rates and corresponding sugar-burning metabolism. Because you have sufficient oxygen at fat max heart rate, you can estimate this pace as one where you can converse or recite the alphabet without getting winded. However, it’s important to be precise with this measurement in order to achieve the desired benefits of the workout and prevent overstress patterns. For this reason, all exercisers from serious competitors to recreational enthusiasts should get into the habit of monitoring heart rate during every steady-state cardiovascular session.
Carefully monitoring your exercise heart rate will ensure that you conduct a productive, fat-burning workout and avoid the problems associated with overly stressful cardio. You can determine your fat max heart rate by performing a VO2 Max exercise test in a medical or fitness facility, or you can obtain an accurate estimate using Dr. Phil Maffetone’s “180 minus age” formula in beats per minute. For example, a 50-year-old exerciser would have a fat max heart rate of 130 (180 minus 50.) For most devoted endurance athletes, fat max will be surprisingly slow. Consequently, it’s important to set a limit alarm on your heart watch so you will be alerted every time you hit fat max. Setting your alarm five beats before fat max is a great idea, so you can take corrective action by slowing down.
We have been conditioned by culture to maintain a slightly uncomfortable pace in the name of getting a good sweat and a productive workout. However, you will compromise the intended benefits of your training program when you routinely exercise at intensities that are slightly to significantly too stressful to nurture your aerobic development. By slowing down and allowing your body to gradually improve fat burning efficiency, you will become fitter and faster without the risks of burnout that so many athletes suffer from.
Here’s the kicker: Most joggers should really be walking in order to stay at or below fat max heart rate, especially if they are going out for 30 minutes or 60 minutes on a typical training session. Remember, your heart rate will drift higher over the course of a workout, requiring that you slow down toward the end to maintain an aerobic session. While it may be frustrating to slow from your typical jogging pace, disciplined devotion to aerobic conditioning will pay tremendous dividends over the long run, and minimize your risk of injury and burnout that happens when you routinely exceed fat max pace. The next time you head out for an aerobic session, let your heart rate govern your pace instead of trying to stubbornly adhere to a certain pace per mile that is too fast. Remember, walking delivers an outstanding aerobic conditioning effect, even when you have the capability to run at a faster pace.