In our expansive section on Zone 2 training, we outlined many reasons for low heart rate training and discussed many of the beneficial physiological adaptations that occur during base training. These changes have significant positive effects on our overall health and our training.
Whether your goal is broader health gains or athletic excellence, or both, introducing higher training intensity plays an important role, too. Many endurance athletes adhere to a 5-zone training model, emphasizing the importance of spending the majority of training time in Zones 1 and 2. However, a growing body of evidence suggests that strategically and in moderation, incorporating higher-intensity efforts—in Zones 4 and 5—can unlock significant health-related and performance gains.
The Evidence for Training at Higher Intensities:
Paul: Some people are going to be annoyed at this. They're going to say, Waitaminute, I thought you were All Zone 2, All The Time. Others are going to say, I told you Zone 2 wasn't enough. The reality: low-intensity training has always included higher-intensity efforts.
Howard: I know. People want clear-cut answers and perfect solutions. But this is human physiology, not math. Perfect doesn't exist.
Paul: Right. Anyway, 80/20 plans where 80% of your time was spent at low intensity still had 20% of your time, or less, ideally, spent at high intensity. We weren't suggesting you lie down or, you know, play hide-and-seek for the time you weren't Zone 2-ing.
Howard: Higher intensities are part of any fitness plan, and the research is very clear about that, and we've been clear on it too, even if people sometimes choose to ignore that part.
Paul: The key, as you say above, is to make that higher-intensity effort worth it. You need to be 80-90% of your maximum heart rate, and you need to give yourself time to recover, both during and after the session.
Howard: Right. Injuries and detraining may sometimes be good for orthopedic surgeons, but they're bad for you. Don't hurt yourself.
Paul: We will have a lot more of this shortly in our upcoming app and service, so stay tuned.
Howard: You're so promotional.
Paul: I prefer the word "helpful" ;-)
Scientific literature increasingly supports that occasional higher-intensity efforts can substantially benefit endurance athletes as well as people simply trying to improve their general fitness. Studies have explored the physiological responses and adaptations associated with Zone 4 and 5 training, shedding light on why these efforts are not only beneficial but essential for maximizing aerobic function.
For our paid subscribers, the remainder of this article will explore the rationale behind incorporating faster, more intense training sessions into your regimen, focusing on mitochondrial adaptations, lactate clearance, improving lactate threshold, and VO2 max.
