I’ve written before about the difficulties around easy running, but after a particularly tricky run where I was arguing with my heart rate on my watch, I feel it’s worth revisiting.
Us running coaches love the word easy. Why? Because it’s a catch-all term to describe the effort level we need you to run. We have no idea what kind of Monday you will have had when we set your plan, even if we do it weekly. We just know we need you to run some comfortable kms/miles, either to warm up or to recover and reset. So we stick the word easy down, give a broad numerical range of pace or heart rate and send you on your way.
I explained the rationale for trying to nail this notoriously tricky pace in my previous blog – here. Sometimes though it just doesn’t go to plan. Here’s why.
Factors which make easy running not easy
- Weather. The ideal temperature for runners is between 7-15 °C.[1] Running in moderate heat (18-24 °C) can increase your heart rate by 5-10 beats per minute (bpm). Running in hotter still can increase your heart rate by 10-15 bpm or more. While less researched, running in colder conditions are reported to raise your heart rate by 5-10 bpm.[2]
- Dehydration. When you’re dehydrated, the amount of blood circulating decreases, meaning the heart has to work harder to get blood to vital organs. As a result, being 2% dehydrated can lead to a 5-10 bpm increase; 4% sees that rise to 15+ bpm.
- Sleep. We all know we should be getting at least 8 hours of sleep per night, particularly when training. Getting 6-8 hours sleep can increase your heart by 2-4 bpm, while getting less than 5 hours increases it by 5-10 bpm.
- Stress. Stress affects us all differently, although there are some broad patterns. Mild stress – e.g. a work deadline, or busy schedule – can increase your heart rate by 3-5 bpm. Moderate stress – when you’re feeling anxious – sees an increase of 5-10 bpm.
- Illness. When you’re fighting off germs – i.e. before you’ve got any symptoms – your body is working extra hard. As your immune system kicks in, you might be more dehydrated too, so even a mild illness can see an increase of 10-20 bpm.
And the super fun thing about this all is that the effects are additive.
Had a rough night with a poorly child? You’re probably fighting off the germs and had little sleep, so that easy run the day after has increased your heart rate from say 140 to 160. Running in the heat without water? There’s another 25 bpm raise, at least. Worried about work? That’s taking you from 140 to 150 without realising.
It is precisely for this reason we use the word “easy” to describe these runs.
Easy is a state of mind – not a number
The science tells us that multiple different factors alter our heart rate, and therefore our effort levels – it’s one of the main issues with purely heart rate training.
Heart rate can though be used as a cue when life has, well lifed. That easy regular route you do that today feels like a slog isn’t (necessarily*) an issue with you or your training. There’s a whole bunch of reasons why today just wasn’t your day. So slow down, take it steadier and go by perceived effort level where it feels less of a slog and more comfortable. Y’know – easy.
*Final word
There’s one more factor which can impact your perception of easy, and it’s one that appears consistently:
- Fatigue. All runners run through fatigue, particularly those training for longer distances. But chronic fatigue increases stress hormones and makes the body work harder. If you’re regularly seeing your heart rate increased by 5-15 bpm on easy runs and none of those other factors apply, take some rest. Some proper rest. And work with someone to help you plan your training appropriately to you and your lifestyle.
Overtraining is a real risk, even for recreational runners. In fact, even more so – for us, running is, after all, supposed to be fun (even if not always truly easy).
[1] Effects of Weather Parameters on Endurance Running Performance: Discipline-specific Analysis of 1258 Races – PMC
[2] Cold Weather Running: Cardiovascular Adaptations and Safety | Health Crunch
