WHAT IS HRV?

Heart Rate Variability (HRV) provides an insight into your readiness to ride hard, harder or easy each day. If you are a cyclist who loves to ride yourself into shape, how do you know when you might need a break? HRV may be your best guide to taking easy or completely off days.

What is HRV?

If your resting heart rate is 50bpm, that means you’ve got 50 heart beats in a minute. But how evenly spaced are those beats within that minute? Your heart doesn’t tick like a metronome. The beat-to-beat time will vary. HRV summarizes how much, or how little, that timing varies.

HRV provides evidence-based insight into the balance of your autonomic nervous system (ANS). Okay, more background needed here …

What is the ANS?

The ANS is the entire nervous system that’s running without direct control by the attention of your mind. Your Somatic Nervous System (SNS) is all the nerves you can control with your intentional thinking.

Your legs pedal because you think it so using your SNS. But your heart beats without you asking it to do anything. The ANS controls it.

Your breath stands with one foot in both nervous systems. Usually it’s on auto-pilot guided by your ANS. But of course you can also tell yourself to breathe faster or slower, letting you override your ANS with your SNS.

Getting a little deeper into understanding the ANS, it has two branches: parasympathetic and sympathetic. These are important to understand, because HRV gives us insight into the balance between the two.

The parasympathetic branch controls the “rest and digest” operations.

The sympathetic branch controls the “fight or flight” operations. The parasympathetic system is your brake, the sympathetic system is your gas pedal. Both are needed for survival. Dominance (even micro-dominance) of either one can mean problems, especially for an athlete in training.

Measuring HRV provides the most direct insight to the state of your parasympathetic branch. By extension it gives clues to your state of recovery.

Interpreting Your HRV

In general terms, you want to see a high time variability (high HRV) between heart beats to be in a well-recovered state. When HRV drops low, there’s too much “gas pedal” still coming from your sympathetic branch, even at rest.

Usually a higher HRV means you’re primed to handle a big training stress, like a super hard interval workout.

Too high or too low means something is out-of-whack. You need a steady and easy ride, or a complete day off training.

There is no particular HRV to target. We have our individual HRV ranges. These

emerge from our genetics and training histories.

It’s important to track your HRV over time. Then start looking for deviations from your own average. Use a daily training journal. Track not only your workouts, but how you feel, how much sleep you’ve been getting, and how much non-training stress you’re under. These will give context to your daily HRV.

When a coach can’t look you in the eyes, seeing dark circles under them, you might not fully understand you need a day off. HRV can make the observation for you, at a deeper level than even your coach.

The ideal HRV state is a stable day-to-day morning HRV reading. Large swings show you aren’t recovering well. It might mean more than just a day off training, because HRV is also affected by:

• The length and quality of your sleep - you cannot sacrifice sleep and optimize recovery

• High fasting blood sugar levels usually caused by snacking on too many sugary treats throughout your day, and particularly in the evening before sleep

• Mood state disturbances - feeling down or depressed, especially when being active is normally associated with an increase in feelings of wellbeing and satisfaction with life

• Dehydration - plasma is the liquid part of your blood that blood cells float around in. With plasma below normal because of dehydration, your heart beats faster to maintain blood pressure

When your HRV falls below your normal range, take the day off. Also assess your sleep, snack, stress and hydration statuses. Take advantage of the “missed” workout to make plans and take action around improving your overall recovery status.

Keep in mind it’s normal to have a low HRV on event day. Jitters are a regular part of everyone’s race experience. Butterflies will likely show in your HRV as the “fight or flight” response lowers your normal values. If you’ve had solid training in the weeks and months before, it won’t impact your performance.

Common advice is to ignore your HRV on event day, so it won’t undermine your confidence. Go ride the best you can.

Apps to Measure and Track HRV

The straightforward method to track your HRV is with an app on your smartphone or tablet. Hrv4training, ithlete and Elite HRV are all easy to use examples. Hrv4training can even grab an HRV reading using your finger placed over the camera lens.

Best practices for measuring HRV are:

• Consistency – take a reading at the same time of day (upon awakening is best) every day to build and maintain your baseline

• Use the same method every time – always use the camera or an approved Heart Rate Monitor (HRM) strap. Not all HRM straps provide the correct granularity of data to calculate HRV. The Hrv4training app can also use an Apple Watch. All the apps above tell you which devices they’re compatible with

• Sit up or stand up, wait one minute, then take your reading – research suggests the small challenge of moving from lying to standing creates just enough stress to make HRV changes stand out better in long-term athletes with extremely low resting heart rates

• Do not swallow when taking the reading – the swallow reflex will throw off your HRV enough to make a measurable difference

• Breathe naturally – in your own selfpaced fashion without fidgeting while taking the reading. A specific pacedbreathing rate does not help your reading and can actually get in the way if the pacing is nothing like what you’re used to.

Create Your Feedback Loop

HRV shows a deeper insight into the overall stress on your body than resting heart rate alone. But you will need to build and maintain a baseline of readings to make it useful. Take morning measurements at least four days a week. Everyday if you can. Keep it up and build a rolling seven day average inside whichever app you choose.

Then use the feedback from your HRV to avoid burning out. You’ll discover days to step back and self-evaluate the decisions you’ve been making. It will help you take the time to think about balancing all the stressors on and off your bike.