Whether your goal is burning fat, building endurance, or increasing speed, this strategic approach helps you work smarter–not harder.

Written by Shelley Russell
Photography by James Patrick

I vividly recall a day from eight years ago as if it were just yesterday. I was pushing my spin class into the red zone when I noticed a man kneeling to my right with a big camera aimed at me. Later, he emailed me the photo above and explained, “I love to capture people in their elements.” As a tech geek, I can’t help but smile when I think about it; he certainly did capture me in my element!
As a personal trainer and group fitness instructor, I use heart rate training to help my clients maximize their workouts. Through a database containing all my clients’ statistics, I use this information to develop their customized heart rate zones. Whether training in -person or online, designing your workouts based on heart rate zones can take your fitness to the next level in a totally safe way.

WHAT IS HEART RATE TRAINING?

Heart rate training uses heart rate monitors to track beats per minute during exercise. These numbers indicate the energy zones you are working in, revealing whether you are burning fats or carbohydrates and working aerobically (with oxygen) or anaerobically (without oxygen). This information also indicates whether you are using slow-twitch or fast-twitch muscle fibers. All these factors are essential because they ensure you are targeting the zones that will help you achieve the results you are looking for in your training program.

BENEFITS OF HEART RATE TRAINING

Heart rate training has a lot to offer when it comes to improving your fitness. It not only boosts your cardiovascular health but also helps you focus your workouts based on your specific goals, whether that’s burning fat, building endurance, or increasing speed. By keeping an eye on your heart rate, you can avoid overtraining and reduce your chances of getting injured. Plus, tracking your heart rate lets you see how much you’ve improved over time. It also helps you plan better recovery days, which can lead to even better performance. The real-time feedback can keep you motivated, pushing you to stay in the right intensity zones during your workouts.

HEART RATE TRAINING IN ACTION

ZONE 1: If I put a client named Jane Doe, who wants to start a fitness program but hasn’t regularly exercised in many years, on the spin bike with a heart rate monitor, I will keep her heart rate in the “Aerobic-Base Training Zone.” This means I will keep her heart rate low aerobic, or at 50-60% of her max heart rate (if you’re using an Apple Watch, the colors on it will mostly be blue). I want to build her aerobic foundation without putting too much stress on her heart. I’ll concentrate on maintaining a steady pace and comfortable resistance on the bike.

This phase is about creating a positive exercise experience so that Jane can increase the capillaries responsible for carrying oxygen to her slow-twitch and fat-burning muscle fibers. It’s also about improving heart strength so that she can pump more blood over time without too much stress on her body. Jane’s RPE, or Rate of Perceived Exertion, will be 5.5 to 6.5 out of 10, and talking will be effortless.

ZONE 2: Jane should aim for consistency by exercising 2 to 3 times per week for up to 30 minutes per session throughout 4 to 6 weeks. By doing so, she will start to notice improvements in her overall health and be prepared to bring her heart rate into the “Aerobic Training Zone.” During this time, Jane may also observe some weight loss as her body builds more mitochondria to process body fat for energy. In Zone 2, Jane should target 60-70% of her maximum heart rate, and she will see mostly teal on her Apple Watch. Talking is comfortable in this zone.

While training here may not be intense enough to significantly improve VO2 max—her capacity to transport more oxygen to her working muscles with fewer heartbeats—it can still help reduce the occurrence of many “diseases of civilization,” such as insulin resistance and heart disease. I will increase Jane’s resistance on the spin bike and tackle some hills to train her heart in Zone 2, which still focuses on slow-twitch and fat-burning muscle fibers.

ZONE 3: In Zone 3, Jane has reached “The Happy Place.” This is where Jane has improved her cardiovascular system, enabling her to handle more resistance and effort without creating stress in her body. In other words, Jane is now on the road to being physically fit. She has developed a more efficient fat-burning aerobic system and can utilize oxygen more rapidly in her newly created mitochondria within her stronger and larger muscles. If Jane had been hoping to lose weight when she started training, she would have been happy with the results she had seen so far.
In Zone 3, Jane sees mostly green on her Apple Watch, and she is working at 70-80% of her max heart rate. Her RPE is 7-8, and talking is still comfortable. I will introduce intervals and standing flats to Jane; she will love them! While primarily focusing on slow-twitch, fat-burning muscle fibers, we will begin to engage her fast-twitch, carbohydrate-burning fibers during the intervals.

ZONE 4: Jane and I are approaching the 3–4-month mark in our training, and we are excited to see the orange color on her Apple Watch. Zone 4 training is our first step into the “Anaerobic Training Zone,” where we aim to improve Jane’s VO2 max. This is essentially athletic training in a nutshell.

In Zone 4, Jane will mainly burn carbohydrates because she will be working at an intensity too high for fat to be converted to energy. This means there won’t be enough time to break everything down with oxygen. We aim for 80-90% of Jane’s max heart rate with an RPE of 8 to 8.5, where talking is difficult. During this phase, we will do more intense bike intervals with speed and resistance. Jane will notice her muscles becoming more toned as the fast-twitch muscle fibers increase in size with her newfound power.

ZONE 5: The final zone that Jane and I will target at about the 5–6-month training mark is Zone 5, more commonly known as “The Red Zone.” On Jane’s Apple Watch, she will see pink. This zone corresponds to 90-100% of Jane’s max heart rate, and she will have an RPE of 8.5 to 9.5 and will not be able to talk.

This zone represents the highest intensity of exercise, where lactate is produced and eliminated. It’s also known as the “Athletic Improvement Zone,” focusing on the immediate energy sources of creatine phosphate and ATP. Jane can only push in this zone for about 8-10 seconds as she uses that energy. The idea is to improve these energy pathways for the all-out burst in a race.

Although Jane and I won’t spend much time here, we will challenge those pathways to keep them alive and in check. Jane will now feel fit with her more robust and healthier cardiovascular and muscular systems.

If you haven’t started training with heart rate zones yet, I really encourage you to give it a shot. Understanding the “why” and “how” behind your workouts can lead to safer and quicker results. Plus, it makes your training much more effective by targeting specific goals, whether it’s fat burning, building endurance, or improving speed. I recommend finding a trainer certified in heart rate training; they can create a personalized program just for you. This way, you’ll get the most out of your workouts and make steady progress on your fitness journey.