Maximize Your Cardio Program Part 2:
Part 1 of this series of articles on cardiovascular training discussed how you can achieve changes in your body at the cellular level, such as increased capillary density, increased aerobic enzyme activity, and increased density and distribution of mitochondria within cells, by training at a moderate pace of about of your 70% VO2max. In practice, this means you can increase your energy output and increase your work capacity by performing continuous large muscle group exercise at a conversational pace for the entire length of your workout.
However, to increase your efficiency to allow you to do more work for the same amount of effort, you need to work at higher intensities for about 10 percent of your total training time. Higher intensity work will increase your tolerance for harder work. This type of training is called lactate threshold training. Your lactate threshold is the highest intensity at which you can work while producing energy aerobically. For example, elite endurance runners race just below lactate threshold. They are extremely efficient and work aerobically at paces that novice athletes consider sprinting. However, the highly trained athlete racing at lactate threshold is working at a pace that is no more stressful for him than a novice athlete working at lactate threshold but at a much slower pace.
If you work at an intensity higher than lactate threshold, your body’s capacity to produce energy with oxygen exceeds the demand for energy. The higher demand for energy requires your body to produce energy via one of the short-duration anaerobic pathways. You will be able to work through anaerobic conditions for a short time, possibly only seconds or minutes. Your body increases into lactic acid production to use the acid to produce energy. The increased acid causes pain and fatigue in the muscles and decreases performance. Hence, endurance athletes strive to increase their aerobic energy production capacity and steadily increase their tolerance for higher intensities and longer duration of exercise.
However, even non-athletes benefit from increasing lactate threshold. Stay-at-home moms probably would agree that they could never have too much energy to keep up with their children. Increasing your lactate threshold allows you to climb stairs, crawl on the floor, wipe up messes, and pick up little ones hundreds of times a day without back-breaking fatigue. A commuting office worker might need to run to catch a train and avoid waiting an hour for the next one. In a sense, we all are endurance athletes trying to increase our daily efficiency. We can never have too much energy.
Fortunately, anyone can increase their efficiency in a relatively short amount of time each week. Here are some guidelines:
1. Work at a “comfortably uncomfortable” pace which equals about 80 – 85% of your VO2max. This is about 1 to 2 steps up from your conversational pace required to increase cellular adaptations. Work hard but not too hard. You should be able to say a few words at one time but not carry on a conversation;
2. Keep the duration of threshold training to about 10 percent of the total cardiovascular training volume for the week; typically, this means 20 to 40 minutes of activity at threshold intensity but varies depending on total volume;
3. You may perform continuous threshold training or split the time into intervals; intervals are periods of threshold work alternated with periods of lower intensity recovery; start interval training with short threshold intensity periods followed by longer recovery periods such as 2 minutes threshold/ 4 minutes low intensity and gradually decrease the rest periods.
4. You do not need to sprint like Carl Lewis; just challenge yourself to do a little more than you are comfortable;
5. You do not necessarily need to increase speed; walking or jogging uphill might stress your cardiovascular system as much as increasing speed on flat terrain. Listen to your body.
6. Always warm up and cool down at least 10 minutes each before and after threshold training; perform about 1 session of threshold training per week for 3 to 4 weeks and then take a break from threshold work for a week.
Your body will tell you if you did too much. If you feel sore beyond one day after exercise, you probably worked too hard and need to cut back intensity for a session or two. If you do not feel sore, but you are tired and cranky, that is also a sign you are doing too much too soon. Remember, the goal is to do just enough to increase your energy.
Part 3 will discuss the third level of cardiovascular training: decreasing your resting heart rate through VO2max interval training in just minutes a week.
Daniels, Jack. “Incorporating Sport-Specific Skills into Conditioning: Distance Running,” within High-Performance Sports Conditioning, Bill Foran ed., Human Kinetics, Inc. 2001.