For today’s edition of Dear Mark, I’m answering two questions from readers. First one comes from Debbie, a prolific hiker and backpacker who can’t seem to shake terrible thigh muscle cramps during steep climbs. She’s tried all the conventional advice. She’s taking electrolyte tabs. She’s staying hydrated. Nothing works. What does? And then, Brad wonders about parasympathetic overtraining, a type of overtraining you don’t hear much about. What does it mean and how should he respond?
Let’s go:
Read MoreFor today’s edition of Dear Mark, I’m answering three reader questions. First, if things are going well on a relatively low-calorie intake, should you just keep on keepin’ on or should you increase food intake to “get ahead” of your needs? Next, what’s the deal with a study showing a high-carb diet is better for testosterone levels than a high-protein one? What does this mean for your Primal way of eating? And finally, can an improvement in heart rate variability after a carb refeed indicate a greater need for carbs?
Let’s go:
Read MoreRegular Mark’s Daily Apple readers know of my enthusiasm for the cutting edge biofeedback technology known as heart rate variability (HRV). There is a detailed introductory post here, and a follow up post here. In short, HRV measures the variation in beat-to-beat intervals of your heart, providing a direct window into the functional state of your autonomic nervous system. A high HRV score (indicative of more variation in beat to beat intervals) suggests a synchronistic balance between your parasympathetic (“rest and digest”) nervous system and your sympathetic (“fight or flight”) nervous system. A lower than normal (for the individual) HRV score is indicative of sympathetic dominance—a state of overstress or poor cardiovascular function.
Read MoreEven if you don’t really understand the ins and outs of heart rate variability (HRV), you’ve probably heard that high HRV is “good,” while low HRV is “bad.” That generalization is a bit too simplistic, but it’s more or less correct. HRV is a measure of how much the intervals between your heartbeats vary. When your heart beats like a metronome, with little variability in between-beat intervals, HRV is low. That indicates that your body is stressed and your sympathetic (“fight-or-flight”) nervous system is highly activated. On the other hand, when your heartbeat is more irregular, HRV is high. That signals low physiological stress; your parasympathetic (“rest-and-digest”) nervous system is relatively more dominant. It’s not exactly intuitive, I know. Here’s all you need to remember: All else being equal, higher HRV is better than lower HRV. High HRV means you’re rested and recovered, probably sleeping well, and not overly stressed. That’s why athletes use HRV monitoring to plan their workouts and rest periods, PR attempts, and deload weeks: it eliminates the guesswork. Even if you’re not an athlete, HRV is a strong diagnostic biomarker for general health and resiliency. Here we face a quandary, though. What constitutes a high versus low HRV? An excellent question to which there is no easy answer. “High” and “low” are relative for each individual. We all have a baseline, normal HRV around which we fluctuate based on how stressed or relaxed we are, whether we worked out hard or imbibed too much the previous day, and so on. What’s high for me might be low or middling for you, and vice versa. Furthermore, average HRV differs as a function of age, sex, and how active versus sedentary you are. The goal is to keep HRV high whatever that means for you. Unless you’re one of the rare individuals who is happy unbothered all the time, that means engaging in practices that help your body buffer the stress you inevitably experience in the course of modern life. Here are 14 ways you can do that. How to Increase Heart Rate Variability The following tips are researched-based methods for increasing your HRV. In an ideal world, your chronic stress would be as low as possible all the time, and you’d be checking all these boxes on a regular basis—but that’s not realistic. No one can do them all; I certainly can’t. Failing to accomplish one or several or even most of these won’t necessarily result in rock bottom HRV. Maybe you have a job you love, but the commute is long. Maybe green tea makes you jittery and nauseated. I’m just giving you all the information I have so that you can find a system that works for you. Oh, and I won’t go into the normal stuff that positively impacts our HRV, like getting enough sleep and regular, not-too-draining exercise. The basic health stuff we talk about all the time here is all important for HRV, but the benefits are implied and don’t require further … Continue reading “How to Increase Your Heart Rate Variability”
Read MorePeople are always looking for that one biomarker to rule them all, the number on a paper that absolutely determines your health, longevity, fitness level, sex appeal, happiness, and productivity. Throughout the years, it’s bounced around as researchers think they’ve found “IT”— from LDL to BMI to ApoB to CRP to blood pressure to A1c and back again. But we always come up wanting. The “one biomarker” never pans out because biology is complex and irreducible to a single number.
However, there is one biomarker that shows promise as a broad indicator of overall health and fitness: heart rate variability (HRV). In today’s post, I’m going to provide an overview of HRV—what it is, what makes HRV “good” or “bad,” why you should seriously consider tracking it, and how to get started.
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