The difference between top bike racers and us mortals is that they vary the intensity while we ride at about the same level of effort most of the time. Varying the intensity of workouts is the fastest way to improve.

• Target training more effectively. Each of the three different energy systems (ATP-PC, glycolytic anaerobic and oxidative aerobic) improves from training in different zones. Similarly, the performance of each of the three muscle types (slow-twitch, fast-twitch IIa and fast-twitch IIb) improves from a specific type of training in a particular zone. Depending on your goals you can target your precious training time more effectively.
• Build endurance more effectively. You might be riding too fast to build the most endurance! Slowing down to the right zone will yield more improvement in your available hours a week than riding more time at a too-fast pace.
• Improve power faster. You’ll improve more by cutting back to fewer hours a week with two of the hours in the right zone(s) to build power and more recovery, than if you find a way to increase your training to more hours a week.
• Tailor training to your body. By learning to listen to your body or gauging your lactate threshold or functional threshold power you can tailor the training zones to your fitness.
• Optimal overload. To improve you have to ask more of your body. But if you overload your body too much your fitness may actually get worse, and if you don’t overload it enough your fitness won’t improve. Further, different levels of overload in different zones bring about different adaptations.
• Optimal recovery. Your fitness improves while you are not training hard. You can use the training zones to provide optimal recovery between hard intervals and to determine how much recovery you need between hard days.
• Spare precious glycogen. The amount of glycogen your body can store is limited—just enough for 2-3 hours of hard riding—but everyone carries enough fat to fuel long, less-intense rides. Riding at an endurance pace, you train your body to use more fat and less glucose for fuel. (Training your muscles to burn more fat won’t result in weight loss. That results from burning more calories than you consume.)
• Power produced increases before the glycolytic system kicks in. Training at the proper intensities enables you to ride harder using just aerobic energy before you call on your glycolytic system and start to produce significant amounts of lactic acid.
• Better performance. By training at the right intensities you can ride faster and climb hills better using your oxidative system. You can also produce more power with your glycolytic system. And you can sprint better to outrun that dog!

Download Training Zones—Spreadsheet of training zones by perceived exertion, heart rate and power. Download to calculate your zones.

I’ve written an eArticle:

Intensity Training 2016: Using a Perceived Exertion, a Heart Rate Monitor and a Power Meter to Maximize Training Effectiveness. A 39 page eArticle packed with current information about intensity that discusses further:

1. The benefits of varying the intensity.
2. How to get the most out of limited training time by varying the intensity.
3. How to gauge intensity using perceived exertion, a heart-rate monitor and a power meter and the pros and cons of each method
4. How to vary the intensities in your workouts depending on:
   • Your type of riding: health and fitness, club and endurance rider or performance cyclist.
   • The time of year: preseason, base period, build period and main season.
5. 10 different sets of workouts for 10 different training objectives
6. 5 to 10 workouts within each set including both structured interval-type workouts and unstructured free-form workouts.
7. The importance of balancing overload and recovery

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