Cycling With a Cold, When to Ride and When to Rest

James. Hello, and welcome to the WattPlan Podcast. I'm James. I fit my riding around family, work, building WattPlan and the odd podium, and I read a frankly unhealthy amount of sports science. This week's question turns up every autumn. You wake with a streaming nose and a session in the plan. Can you ride with a cold, or should you rest? Lyra, our AI research voice, has been through the trials, and every study is linked in the show notes.

Lyra. Very timely. A quick word first. This is general information from the guidance and the studies, not medical advice, and I can't diagnose anything. With that said, the straight answer is it depends where your symptoms are. Mayo Clinic's guidance is that shorter, easier exercise is usually OK if every symptom is above the neck and you've no fever. Chest symptoms, a fever or aching muscles mean rest.

James. The neck check. I've heard that one for years. Is it actually based on anything?

Lyra. Ha, that's the honest catch. We looked at three studies for this episode. The first is the International Olympic Committee's 2022 consensus statement on respiratory infections, in the British Journal of Sports Medicine. It calls the neck check expert opinion, and says there's little research behind any approach to returning to sport after an infection. But the research that does exist on exercising with a cold points the same way for mild cases. [1]

James. Go on then. What's the research?

Lyra. Two trials, both by Weidner and colleagues, and they're properly bold. They gave healthy young adults a cold on purpose, using a rhinovirus. In the 1998 trial, in Medicine and Science in Sports and Exercise, 34 people of moderate fitness, aged 18 to 29, exercised for 40 minutes every other day at 70 percent of their heart rate reserve, for ten days. Sixteen others didn't exercise. Symptom scores were no different between the groups, and nor was the weight of their used tissues. [4]

James. Hang on. They weighed the tissues?

Lyra. They did, every twelve hours. The tissue weight stood in for how bad the cold was. And symptoms weren't any worse after a session than before it. So in that study, moderate exercise didn't make the cold worse or longer.

James. And the second one?

Lyra. The 1997 trial, same journal, tested 24 men and 21 women at the peak of their cold, the day after the second dose of virus. Their lung function, their responses at submaximal efforts and their maximal exercise performance were no different from before they caught it. One detail to know, the maximal tests were running trials, not cycling. [5]

James. Really? So a cold doesn't touch your engine at all?

Lyra. For a mild cold that stays in the nose and throat, that's roughly where the IOC lands too. Lung function and VO2max, the most oxygen you can use, hold up. But moderate to severe symptoms are more likely to hurt performance. And a cold can still cost you indirectly. A blocked nose disrupts sleep, and some cold medicines, antihistamines among them, may impair exercise performance.

James. But surely everyone tells themselves it's just a cold. How do you know when it isn't?

Lyra. Right, this is the important bit. The IOC lists the signs of a more severe infection as a headache, symptoms through the whole body like malaise, fever, muscle aches and fatigue, symptoms that drag on, symptoms getting worse rather than better, and new symptoms appearing. The NHS adds that a cold comes on over two to three days, while flu arrives within a few hours and leaves you too exhausted to carry on as normal.

James. And when should someone actually see a doctor?

Lyra. The NHS says see a GP if you've a high temperature for more than three days, chest pain or shortness of breath, no improvement after ten days, or a cough for more than three weeks. And see a GP when cold symptoms start if you have a long-term condition, such as diabetes or a heart, lung or kidney condition, or a weakened immune system. Anything beyond a simple cold, chest symptoms or a fever, is a question for a doctor or pharmacist, not a podcast.

James. What about riding indoors? Is the turbo any better?

Lyra. For the people you'd otherwise ride with, yes. Colds spread most in the first few days, and the NHS says you're infectious until every symptom has gone, usually one to two weeks. An easy turbo session keeps your cold out of the club run and the café stop. And if you've a high temperature or don't feel well enough for your normal day, the NHS advice is to stay at home, avoid other people until you feel better, and drink plenty of fluid.

James. Okay, let's split it by rider. If you're new to this, what's the simple version?

Lyra. If you're new to structured training, ask one question before every ride. Where are my symptoms? Above the neck with no fever, a shorter, easier spin is usually OK, and so is not riding at all. Below the neck, a fever or aches all over, rest. And a few days lost to a cold cost your season very little.

James. And if you train with power or heart rate, and you're watching your Fitness line drop?

Lyra. Ha, that was always coming. WattPlan's Fitness is a 42 day weighted average of your daily Load. So three days off lowers it by about seven percent, and a full week by about fifteen and a half. It climbs back as you ride again. It measures the training you've absorbed, so a dip during a cold reflects the days you didn't ride. It says nothing about your health. Save the intervals for when you're clear.

James. And if you race?

Lyra. If you race under anti-doping rules, check your cold remedy. Pseudoephedrine, which is in some multi-ingredient cold and flu medicines, is a stimulant the World Anti-Doping Agency prohibits in competition above a set threshold. WADA advises stopping it at least 24 hours before the in-competition period, which starts just before midnight the day before your race. A pharmacist or doctor can suggest an alternative.

James. So when can you go back to the hard stuff?

Lyra. In steps, rather than straight into your next interval session. The article suggests your first ride back be a test you run yourself, ten to twenty minutes at 60 to 70 percent of your usual intensity, checking how you feel during it and over the next 24 hours. Stop and talk to a doctor if you get excessive fatigue, breathlessness, chest pain, dizziness, a heart rate racing faster than normal, or muscle or joint pain. Mayo Clinic's advice is to return to your normal routine gradually as you start to feel better.

James. And if I tell the WattPlan Coach I've got a cold?

Lyra. It suggests a recovery block of two to seven days, as rest days or short easy rides. It changes nothing until you agree, it's told never to diagnose, and if you ask it a medical question, it tells you that one's for your GP. Rest days in the block never count as misses, so it's worth telling it. When the block ends, the plan picks up as written, so if your first day back is intervals, ask the Coach to make it an easy ride.

James. Surely, though, those trials don't tell us much about a club rider doing threshold intervals?

Lyra. You're right, and that's where the evidence runs out. Both trials used adults aged 18 to 29, one rhinovirus given in a laboratory, and moderate exercise. So they say nothing about hard intervals, older riders, or the colds you pick up at home. Neither measured power on a bike during a cold. And the first-ride test is guidance written for every sport, not a protocol tested in cyclists.

James. Right, homework. What do I do the next time I wake up snuffly?

Lyra. Three things. One, do the neck check before every ride. Above the neck with no fever, ride shorter and easier, ideally on the turbo for the first few days. Two, if the NHS signs show up, a high temperature for more than three days, chest pain or shortness of breath, or no improvement after ten days, see a GP. Three, make your first ride back short and easy, asking the Coach to swap it if the plan has intervals that day, and check how you feel over the next day before building up.

James. Okay, in my words. Check where it is, keep it easy and indoors, rest if it's in my chest, see the GP if those signs show up, and come back gently. And the Fitness dip is just the maths.

Lyra. That's it. Take the easy ride or the rest day the guidance points to, and save the intervals for when you're clear.

Lyra. The full article and every study we mentioned are on the WattPlan blog, linked in the show notes.

James. And if you want a plan that's built around the time you've actually got, that's what WattPlan does. Thanks for listening.

Voices produced with ElevenLabs. James's voice is a clone of his own, Lyra is an AI voice, and James reviews every script before it is published.