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A different approach to an easy run
On Sunday, my Garmin suggested a 57-minute run at nine-minute-mile pace (5:35 per kilometre). According to the watch, this was supposed to be an easy session. There's just one problem: I always find I need to run a little slower than that, usually around 9:15 per mile (5:45 per kilometre) or slower, if I want to keep my heart rate below 135 bpm.
I'm not particularly bothered about running slowly, and I understand the importance of easy miles. But sometimes, when you're watching your pace creep up and your heart rate follow it, you start wondering whether there's another way of approaching things.
I decided Wimbledon Common would be a good place to find out. Dodging dogs and their leftovers, eyeing up runners in the distance and trying to close the gap, exchanging the occasional gentle nod with runners coming the other way. You know the sort of thing.
On the short jog over to the Common, I decided I'd do ten miles, but change tack. Rather than settling into a slower, continuous 9:15-ish pace, I would walk for around a minute every mile, then pick up the pace and make up the time. I had no idea whether this would benefit me, but I could at least compare how I felt, my average heart rate and my overall pace against a more conventional, slower run. It wasn't a scientific experiment, but it gave me something to measure.
The Sunday experiment
The idea was simple. I'd run most of each mile at a quicker pace, walk for roughly a minute, and then get moving again. I wanted to see whether the short recovery periods would let me run more comfortably at a quicker pace without feeling as though I was constantly pushing.
And something interesting happened. During the faster sections, I started feeling stronger and stronger, and towards the end I was getting the average mile pace down towards 8:15 (5:08 per kilometre), including the walking minute. I felt good and, more importantly, I felt as though I had more to give.
Sunday: 10.01 miles
- Distance: 10.01 miles (16.11 km)
- Time: 1:28:45
- Average pace: 8:52 per mile (5:30 per km)
- Average heart rate: 145 bpm
I wanted to keep my heart rate lower, but I got a little carried away. Initially I was trying to bring the average pace for each mile under nine minutes, and as I started feeling stronger, that became a bit of a game: could I get the average under 8:30? It was probably a case of getting a little too enthusiastic, but I finished feeling pretty good.
The Monday comparison
I wanted something to compare Sunday's experiment against, so I looked back at the previous Monday, when I'd completed an eight-mile run. This was a continuous run, without planned walking breaks, and I'd been well rested beforehand. The average pace was almost identical to Sunday's.
Previous Monday: 8.01 miles
- Distance: 8.01 miles (12.89 km)
- Time: 1:11:00
- Average pace: 8:52 per mile (5:30 per km)
- Average heart rate: 152 bpm
There's another detail worth mentioning. Sunday wasn't completed on fresh legs either: I'd been to parkrun on Saturday, about four miles including the jog there and back, at moderate effort. So I had some running in my legs going into the ten-mile experiment.
Yet the difference in how I felt was noticeable. On Sunday I finished ten miles at the same average pace as Monday's eight, with a lower average heart rate, and I felt strong with plenty left in the tank. Monday's continuous run had left me feeling considerably more fatigued. The weather was similar, which was another useful point of comparison.
Part of that lower average heart rate will simply be the walking minutes bringing it down, so it isn't a like-for-like comparison of how hard I was running. And I don't want to pretend this was a controlled experiment. The distances were different, the sessions weren't performed under identical conditions, and there are plenty of variables that could have influenced the results.
Still, it's an interesting observation. I'd run further, at the same average pace, with a lower average heart rate, despite having run the previous day. Was it the walking breaks, the different pacing or something else entirely? I don't know, but it made me want to investigate further.
What happens to your heart rate when you walk?
When you run, your muscles need more oxygen. Your cardiovascular system responds by pumping more blood around your body, and your heart rate rises. When you start walking, the demand generally falls and your heart rate begins to come down.
It doesn't happen instantly, though. Heart rate takes time to respond to changes in effort, so a one-minute walking break won't necessarily bring you back into Zone 2. But repeated walking breaks can give you chances to recover before the next running section, which could be particularly useful for runners who struggle to keep their heart rate under control during continuous easy running.
There's a distinction worth making. Walking doesn't automatically make a session an aerobic or Zone 2 workout; that depends on the overall intensity and your individual aerobic thresholds. Equally, if you can run continuously at an easy aerobic intensity, there's no reason to introduce walking breaks simply for the sake of it.
What does the research say about run-walk training?
One study that caught my attention was by Kuno Hottenrott and colleagues, Does a run/walk strategy decrease cardiac stress during a marathon in non-elite runners? (opens in a new tab), published in the Journal of Science and Medicine in Sport in 2016. The researchers looked at 42 non-elite marathon runners, comparing a planned run-walk strategy with continuous running.
The run-walk group finished in an average of about 4 hours 14 minutes, and the continuous-running group in about 4 hours 8 minutes, a difference that wasn't statistically significant. Interestingly, the run-walk group reported significantly less muscle pain and fatigue after the marathon. However, the researchers didn't find that the run-walk strategy reduced cardiovascular stress: both groups experienced similar changes in cardiac biomarkers.
So walking breaks may help some recreational runners manage the muscular discomfort of a marathon without significantly affecting their finishing time, but that doesn't mean they automatically reduce the strain on the heart. It's also worth remembering that this was a marathon study, not a comparison of two ordinary ten-mile training runs.
Is there an energy cost to walking breaks?
Here's where things get interesting. A 2021 study by William Nolan and Andrew Moore, Run-walk marathon pacing: the energy cost of frequent walk breaks (opens in a new tab), published in the International Journal of Performance Analysis in Sport, examined the energy cost of alternating between running and walking. Thirty recreational runners completed different treadmill sessions, including continuous running and alternating two-minute periods of running and walking.
The researchers found that alternating between running and walking required approximately 6% more energy per kilometre than continuous running at the participants' selected paces. The reason is that changing speed repeatedly has an energy cost: every time you move from walking back into running, you have to accelerate again. The walking breaks also produced only a very small reduction in perceived exertion.
That's an important counterpoint to my own experience. Just because I felt stronger using walking breaks doesn't mean the approach was more energy-efficient. There are limitations, too. The study used short treadmill sessions and two-minute intervals, and it didn't look at a one-minute walking break every mile over a ten-mile outdoor run.
Why do experienced runners spend so much time running slowly?
There's another side to this discussion. If you've followed a structured marathon programme, you'll probably have noticed how much of the training is supposed to be easy. It's not unusual for endurance runners to spend around 70–80% of their training at low intensity, with the rest involving harder efforts. This isn't about running slowly for the sake of it. Low-intensity training lets you build volume while managing fatigue, developing the aerobic system that supports endurance performance.
A study by Jonathan Esteve-Lanao and colleagues, Impact of training intensity distribution on performance in endurance athletes (opens in a new tab), published in the Journal of Strength and Conditioning Research in 2007, followed 12 sub-elite endurance runners over five months. One group did a greater proportion of their training at low intensity, below their first ventilatory threshold, while the other spent more time in the moderate-intensity zone. Both groups kept a similar amount of high-intensity training, and the group doing more low-intensity training improved their 10.4km cross-country performance significantly more.
It's a small study, but it supports an important principle: letting too many runs drift into that moderately hard territory may not be the best way to develop endurance.
This is where I'd be careful about drawing conclusions from my Sunday run. My average heart rate was 145 bpm, well above the 135 bpm I was hoping to stay under, so I wasn't necessarily doing the easy aerobic session Garmin had suggested. I had changed the nature of the workout.
So, was my run-walk experiment better?
I genuinely don't know. Sunday's run was longer, had the same average pace as Monday's and a lower average heart rate, and left me feeling considerably stronger. That's enough to make me want to try it again.
But there are a few things I wouldn't claim from two runs:
- That walking breaks are more efficient than continuous running.
- That they automatically reduce cardiovascular stress.
- That a lower average heart rate means a better training adaptation.
- That running faster with walking breaks will improve everyone's aerobic fitness.
What I can say is that it gave me a different way of approaching a ten-mile run, and the experience was noticeably different. The next step is probably to repeat the comparison over several weeks, using similar routes, distances and conditions, and see whether the results hold up. I'd also like to keep the walking breaks but be more disciplined about the running sections, rather than letting myself chase a faster average pace.
My take
I think we sometimes get too caught up in the numbers on our watches. We look at pace, heart rate, zones and training recommendations, and can end up believing there's only one correct way to complete a run. But training isn't about winning every session. Sometimes you need to run slowly, sometimes you need to walk, and sometimes you need to push harder.
My little experiment hasn't proved anything, but it has made me question whether a slower continuous run is always the best option for me. That's probably the most useful thing about it: it has given me something to test, rather than simply following the same approach because that's what I've always done.
If you're a runner who regularly takes walking breaks, or someone who has experimented with different ways of managing your heart rate, I'd love to hear how you approach it. And if you fancy some company on your next run, you can find runners at your pace, organise a local run or discover a neighbourhood running community through Run Love Sprint.
Sometimes, a different approach is all it takes to enjoy the miles a little more.
This article is based partly on my own running experience and is for general information. Two individual runs cannot establish the effectiveness of a training method. Adjust your training to your fitness and recovery, and seek professional advice if you experience persistent pain or unusual symptoms.
