A couple of years ago, on a Sunday in November, Ramesh Kanjilimadhom, the founder of the Soles of Cochin running group, noticed that he was running much slower than his usual pace. Kanjilimadhom, who has finished the Boston Marathon multiple times, and a veteran of sub 3-hour marathons, was keeping me company as I was returning to running after a break. When I apologised for slowing him down, he pointed out that more than 80% of his runs are at paces much slower than his race pace. “The bulk of your running training should be easy runs, just fast enough to let you have a choppy conversation; not faster, not slower," he told me.
The training protocol he was talking about—without actually naming it—was Zone 2 training, a concept that has been widely adopted by endurance sport athletes, especially cyclists. There are five heart rate zones (called just “zones"), based on the percentage of one’s maximum heart rate. Everyone’s heart rate zones are unique, based on individual levels of fitness and conditioning. These zones, or intervals, are used to determine one’s exertion during a workout.
“Zone 2 training is often referred to as the aerobic zone, where the athlete works at an intensity that is sustainable for longer periods of time without accumulating too much fatigue and is capable of using oxygen to generate or yield energy," explains Preeti Shetty, senior sports scientist (strength and conditioning), at the Kokilaben Dhirubhai Ambani Hospital in Mumbai. “In different heart rate zones, the body uses different source as fuel to create energy for your cells, which drives particular reactions in the body. In Zone 2, the body uses fat as a source of fuel more effectively, which helps endurance athletes to sustain their energy level for longer duration.
Zone-based training has become popular among recreational athletes, in part due to the use of smart watches and activity trackers, and greater awareness about the advancement in sports science. “Zone 2 training is a great way to improve your aerobic fitness without getting too tired or risking injury. It helps your body use energy better and delays fatigue, which is useful for endurance activities and even sports such as weightlifting and sprinting. Resistance training boosts your body's ability to recover and handle high-intensity workouts. Building your aerobic system and endurance through Zone 2 training can make you recover faster during intense exercises, making you stronger and faster," says Shetty.
Studies have shown that Zone 2 training is quite beneficial to those who include it in their workout plans. A study conducted as early as 2001 and published in the Journal Of Sports Medicine, showed that athletes who did Zone 2 training after a hard workout showed improved recovery compared to those who did not. Another study published in the same journal in 2014 established that endurance athletes who trained in Zone 2 for six weeks showed significant improvements in their aerobic, endurance capacity, and that their bodies burned fat more efficiently.
Zone 2 training increases maximal oxygen uptake (VO2Max), an essential indicator of aerobic capacity, says Shetty. “By training at light to moderate intensity, you are able to use oxygen to produce energy and to sustain the activity for a longer period of time without becoming fatigued. Zone 2 training also helps in fat metabolism and weight management. When one works at a moderate intensity, their body is able to use fat as a fuel source more efficiently, which helps them sustain their energy levels for longer durations," says Shetty.
Since Zone 2 training leads to improved blood flow to the muscles, it can help reduce soreness and aid in recovery. Also, working out at a light to moderate intensity can help improve muscle endurance and flexibility. This, in turn, reduces the risk of injury during training and competition. Zone 2 training also has a positive impact on mental health and attitude. “It has a positive impact both mentally and physically. It helps lower blood pressure, reduces the risk of heart disease, and improves mental health by reducing stress and anxiety," adds Shetty.
Some of the easiest and most accessible Zone 2 training exercises are light to moderate intensity cardio exercises such as brisk walking, jogging, swimming, cycling and skipping. How fast or slow and for how long you do it, depends entirely on your own conditioning and fitness levels. Your Zone 2 is unique to you, and it can improve or deteriorate depending on your fitness levels.
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The easiest way to know whether you are in Zone 2 without using a tracker or smart watch is to use the “talk test". If you are able to speak about 10-15 words virtually unbroken without the need for extra breathing, you are in Zone 2. If you can do more you are going too easy and if you can’t manage 10 words, you are training too hard.
How much time should you set aside for Zone 2 training? This would depend on one’s training status, fitness goals and current fitness levels, points out Shetty. According to Kanjilimadhom, it should comprise 80% of your total training when preparing for a race. Gone are the days when it was widely believed that if you want to run fast, you need to train fast. Your fast runs should be limited to speed sessions, mile repeats and interval training.
Shetty recommends 3-4 sessions of Zone 2 training at 60-70% of your maximum heart rate in order to achieve maximal adaptation. Like Kanjilimadhon, she also maintains that 80% of your weekly training should be reserved for Zone 2 training, and only 20% ought to be reserved for harder workouts. “Depending on their level of fitness, individuals with relatively low activity levels should aim at 30 minutes of Zone 2 training, thrice a week, to start with. For fitter individuals, 45 minutes is the minimum duration per session. As one’s fitness increases, one can gradually build up to 90 minutes with three to four sessions per week," says Shetty.
Shrenik Avlani is a writer and editor and the co-author of The Shivfit Way, a book on functional fitness.
- FIRST PUBLISHED30.10.2023 | 08:00 AM IST