As you are doing intervals you’ve already done the endurance part of your training right? So if you’re doing 5k you can already comfortably run 10k. If not get back on those long Sunday morning runs!
Intervals involve a period of exertion followed by a period of rest. Repeated.
I would politely suggest that you measure your exertion by PACE or SPEED and NOT by heart rate.
Your intervals (excluding the rest bit) need to be ABOVE your target race PACE ie faster. Say 5% faster.
The best intervals for 5k are probably 1km long intervals with 2 minutes rest. Do at least 3 or at most 5. That’s a hard session. And it’s a hard session for ANYONE because the better you are the faster you will be running at. If that’s too easy have only one minute rest.
That is, in fact, probably TOO HARD for most people.
So you might want to increase your recovery time OR shorten the distance.
At the other extreme therefore you might want to do one minute intervals with one minute rest. Repeated at least 12 times and maybe 20 times. The 1km intervals are more effective though.
Or invent your own somewhere in between the two above. I would try and stick to a constant target pace. Perhaps only varying that pace on your last interval/set where you go as fast as possible. You can have sets of intervals where you run for different lengths of time (or distance) but I think that just complicates things. Keep it simple unless you are really bored by your training regime.
Remember though to get your endurance sorted out first.
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Last Updated on 13 November 2025 by the5krunner
My favourite kit and nutrition
- Garmin Fenix 9 Pro — I’ve just bought one.
- Injinji – Runners protect your toes. Avoid discomfort and minor injury. Run more. Run faster. I use them.
- Garmin 90-degree charging adapter — A small keyring adapter you can use anywhere. Essential when away. I use one.
- Garmin charging puck — the fastest and most reliable way to top up your Garmin before a session. I use one.
- Ravemen FR300 — Front light that mounts directly under your Garmin or Wahoo head unit. Keeps your bars clean and your beam pointed where it matters. I use one.
- Body Glide – The blue anti-chafe stick that all swimmers and many runners use. I use it.
- Maurten — The race nutrition trusted by elite athletes. Gels and drink mixes engineered to be easy on the stomach. I use them.
- Garmin Varia RTL515 — A radar rear light that alerts you to vehicles approaching from behind. Pairs with your Edge or Wahoo. I use this model.
- Favero Assioma Pro RS2 — The power-meter pedals most serious cyclists choose. Accurate, easy to move between bikes. I use this model.
- Garmin Forerunner 970 — A serious choice for a pro-grade triathlon watch. I use this.
- Polar H10 — My daily driver for accurate, waking HRV readings.
- Wahoo ELEMNT Roam 3 — The bike computer that has the feature Garmin lacks: usability. I use mine on most rides.
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. ID
