Ease back in after a cold, because with long COVID, pushing can backfire

Key takeaways

• Mayo Clinic’s “above the neck” rule says light exercise is usually fine with a runny nose or mild sore throat, but not with fever, body aches or chest congestion; it’s expert advice, not a tested rule¹.
• The American College of Cardiology’s 2022 guidance says athletes, competitive or recreational, can return to exercise after COVID-19 once mild symptoms that spared the heart and lungs clear, while chest pain, shortness of breath, palpitations or fainting call for heart tests first³.
• In a study of 11 healthy adults around age 67, ten days of bed rest cut leg strength by about 13% and aerobic capacity by 12%⁹.
• With ME/CFS, the CDC says, symptoms typically flare 12 to 48 hours after overdoing it, and in 2021 England’s NICE told clinicians not to offer graded exercise therapy⁵⁶.
• In 2019, a 40-member international expert panel concluded that exercise during and after cancer treatment eases fatigue, anxiety and depression, and the American College of Sports Medicine’s updated advice tells survivors to avoid inactivity¹³¹⁴.

On Oct. 29, 2021, England’s health-guidance agency reversed its own advice⁶⁷.

The National Institute for Health and Care Excellence, or NICE, told clinicians to stop offering graded exercise therapy to people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)⁶. That therapy raised activity in fixed, planned steps⁶. The decision reversed recommendations in NICE’s 2007 guideline on the condition⁷.

Seven British medical bodies, including the Royal College of Physicians, objected publicly⁷.

The fight points to something often missed: how you get back to exercise depends on what made you sick.

After a cold, easy movement is usually fine. After 10 days in a hospital bed, an older adult may need to work hard to win back strength. With ME/CFS, that same hard push can leave you worse for days. This guide covers how to tell which situation you’re in, with a ladder for each.

A cold: the “neck check” is expert advice, not a tested rule

You’ve probably heard the rule. If your symptoms are above the neck, such as a runny nose, stuffiness, sneezing or a mild sore throat, you can usually exercise¹.

Mayo Clinic gives that advice, and so does the South Dakota Department of Health, which credits a Mayo Clinic physician¹². Even then, both say to cut the length and intensity, such as walking instead of running¹².

Skip exercise if symptoms are below the neck: chest congestion, a hacking cough or an upset stomach¹. Also rest if you have a fever, widespread muscle aches or fatigue¹².

The catch: neither page cites a study¹². The neck check is a sensible rule of thumb from experienced clinicians, not something proven in trials.

A few days off shouldn’t hurt your performance, Mayo adds. Ease back in as you recover, and skip group workouts while you might be contagious¹.

Flu or COVID-19: wait out the fever, then think about your heart

The flu and COVID-19 often bring fever, body aches and chest symptoms. By the neck-check logic, that means rest¹.

COVID-19 has its own heart guidance. In March 2022, the American College of Cardiology (ACC) published an expert decision pathway on its heart effects in adults³. What it advised for competitive and recreational athletes³:

• No symptoms at all: You can resume after 3 days off.
• Mild or moderate symptoms that didn’t involve your heart or lungs: You can resume once symptoms clear.
• Infection 3 months or more ago, with no ongoing heart or lung symptoms: No extra testing is needed.
• Heart or lung symptoms that linger, appear once training resumes, or led to a hospital stay where heart trouble was suspected: Three tests come first: an ECG, a troponin blood test for heart damage and an ultrasound of the heart.
• Confirmed myocarditis: No exercise for 3 to 6 months.

Myocarditis is inflammation of the heart muscle. The ACC defines it by symptoms such as chest pain, shortness of breath, palpitations or fainting, plus abnormal heart tests³.

Early in the pandemic, studies at single universities suggested up to half of athletes might develop it after COVID-19⁴. A later registry called ORCCA put the figure at 0.5% to 1%, said Kimberly Harmon, a University of Washington sports medicine physician who helped write the ACC’s athlete advice⁴.

Her summary was plain: athletes who have chest pain during their infection or when they return to play need a workup, and everyone else should return gradually⁴. Her university aimed that advice at athletes 14 to 25, but the warning signs matter at any age⁴.

A hospital stay: bed rest costs muscle fast later in life

In a study published in 2008, researchers asked 11 healthy adults with an average age of 67 to stay in bed for 10 days⁹. They ate enough calories to hold their weight and the recommended amount of protein⁹.

When they got up, their leg strength had dropped about 13%, their stair-climbing power 14% and their aerobic capacity 12%⁹. They also moved less on their own afterward⁹.

The same team’s earlier report, a 2007 letter in JAMA on 12 volunteers averaging 67, found they lost almost a kilogram of lean tissue from their legs, about 2 pounds, in 10 days¹⁰. The University of Arkansas for Medical Sciences, home of senior scientist William Evans, set that beside a separate 2004 study. Adults averaging 38 lost less than half as much over 28 days in bed¹⁰.

That comparison spans two studies, so treat it as a rough guide. And Evans noted that his healthy volunteers were a best case¹⁰. A real hospital patient may also be fighting inflammation and eating poorly, which can speed the loss, he said¹⁰.

The authors called protecting muscle function during hospital stays a high priority⁹. Our muscle article shows that strength responds to training at any age.

Practical steps:

• In the hospital, ask whether you can sit up, stand and walk, and whether a physical therapist can see you before you go home.
• At home, start with short walks and practice standing up from a chair several times a day.
• Ask about rehab. Our article comparing trainers and physical therapists explains cardiac and pulmonary rehab and who qualifies.

Surgery: training beforehand may help, and the evidence is still building

“Prehabilitation” means getting fitter before a planned operation. Programs usually combine exercise with nutrition and stress-reduction support¹¹.

A 2024 review in Current Oncology found that prehabilitation seems to improve fitness and clinical outcomes in cancer surgery, on top of standard improved-recovery hospital routines¹¹. Certainty was low to moderate, the authors said, because studies were small and varied¹¹.

A 2025 analysis in the open-access journal Cureus, pooling five randomized trials in 422 colorectal surgery patients, gives a sense of the size¹². Prehabilitation lowered the odds of any complication by about 40%¹². At eight weeks, prehab patients walked about 51 meters farther in a six-minute walking test than patients who got standard care¹². But there was no clear drop in severe complications¹².

So the evidence is promising but early. If you have surgery scheduled weeks away, ask your surgeon whether a prehab program or a simple walking and strength plan makes sense.

After surgery, follow your team’s activity plan. Our rehabilitation article covers recovery from joint replacement.

Cancer treatment: avoid inactivity, and build toward a plan

People treated for breast cancer were once told to skip exercise for fear of arm swelling. Newer research changed that advice¹⁴.

In 2019, an international roundtable of 40 experts published updated exercise guidelines for cancer survivors in Medicine & Science in Sports & Exercise, and the American College of Sports Medicine updated its guidelines¹³¹⁴. Kristin Campbell of the University of British Columbia led the work¹³. More than 2,500 randomized trials of exercise in cancer survivors had been published since the first guidelines in 2010¹³.

The panel found that exercise during and after treatment improves fatigue, anxiety, depression, physical function and quality of life¹³. It also found that exercise doesn’t worsen lymphedema, a buildup of fluid such as the arm swelling that can follow breast cancer treatment¹³.

The general prescription, as summarized by Breastcancer.org¹⁴:

• Moderate aerobic exercise at least 3 times a week, for at least 30 minutes.
• Strength training at least 2 times a week, with 2 sets of 8 to 15 repetitions.
• Above all, avoid inactivity.

For people with lymphedema after breast cancer, the panel favored a supervised strength program that starts low and progresses slowly¹⁴. Supervised programs in general seemed to beat unsupervised ones¹⁴.

Treatments vary widely, so ask your oncology team which activities are safe for you now and whether a supervised program is available.

Long COVID and ME/CFS: when pushing through backfires

Post-exertional malaise (PEM) is one of four key features NICE uses to flag possible ME/CFS, and the ACC lists it among long COVID symptoms³⁶. NICE describes it as a worsening of symptoms out of proportion to the effort, whether that effort was physical, mental, emotional or social⁶.

The CDC says a crash may hit soon after exertion or several days later, typically worsens somewhere between 12 and 48 hours on, and can linger for days or weeks⁵.

The CDC is blunt about exercise. Workouts won’t cure ME/CFS, it says. Vigorous aerobic routines that help many chronic illnesses aren’t tolerated by people with this one, and the standard exercise advice given to healthy people can do harm⁵.

The CDC’s answer is pacing, also called activity management: finding your own limits and planning rest alongside activity⁵. It warns about the “push-and-crash” cycle, where doing too much on a good day leads to a crash⁵.

The NICE reversal and the PACE debate. The best-known evidence for graded exercise came from the PACE trial, published in The Lancet in 2011 with 641 participants⁶. It reported that graded exercise and cognitive behavioral therapy, a form of talk therapy, led to improvement in many patients⁶.

Critics, including the authors of a 2022 paper on NICE’s decision, argue that the trial relied on patients’ own ratings without blinding, and that it changed its definitions of improvement and recovery from those first planned⁶. NICE’s own review rated the evidence for graded exercise low or very low in quality⁷.

The other side deserves a hearing. The seven medical bodies said the guideline underplays activity, and that the personalized, paced exercise programs used in England’s health service aren’t the graded therapy NICE described and have helped many patients⁷. Two PACE authors also defended their work⁷.

Both sources we used for this history side with the critics, so weigh them accordingly.

Pacing has its own evidence gap. A 2024 analysis found just five studies of pacing for ME/CFS, only two of them randomized trials, and concluded the evidence was too thin to show a benefit⁸. The authors were hopeful about fatigue, but that result fell short of statistical significance⁸.

If you have long COVID. The ACC’s 2022 pathway defines long COVID as new, returning or ongoing health problems 4 weeks or more after infection³. When the main trouble is a racing heart, lightheadedness on standing or lost fitness, it favors short sessions in a reclined or seated position, on a rowing machine or recumbent bike or in a pool. Its starting dose is 5 to 10 minutes a day, built up as fitness returns³.

If your long COVID includes PEM, that plan may still be too much. The CDC’s pacing advice was written for ME/CFS, but its logic fits: let your symptoms, not a schedule, set the pace⁵. A 2025 fact sheet from the group Emerge Australia, hosted by the State Government of Victoria, sums up PEM self-care: stay within your energy limits, break tasks into small steps and rest before symptoms rise¹⁵.

This is where natural-health instincts and the new guidance line up. Rest is treated as part of care, not as weakness, and your own record of how your body responds becomes the main guide.

The return-after-illness ladder

This guide is our own design, built from the sources above. Pick your row, start at the first step, and move up only when the current step feels easy. Your clinician’s advice overrides it.

Situation	Start here	Build up	Stop and get checked if…
Cold, symptoms above the neck, no fever	A shorter, easier version of your usual activity, such as a walk1	Return to normal as symptoms clear	Fever, chest congestion or body aches appear1
Flu or COVID-19 with fever, aches or chest symptoms	Rest until the fever and aches are gone1	A few easy sessions at about half your usual effort, then add more each week	Chest pain, shortness of breath out of proportion, palpitations or fainting34
COVID-19 with no symptoms	3 days off3	Resume your routine gradually4	New symptoms once you start training3
Hospital stay	Sitting up, standing and short walks, as your team allows	Add minutes daily; ask about physical therapy	Any warning sign your discharge team told you to watch for
Planned surgery	Before: a prehab or walking and strength plan, if your surgeon agrees1112	After: your surgical team’s activity plan	Any symptom your team told you to report
Cancer treatment	Light activity, such as walking; avoid inactivity14	Toward aerobic exercise 3 times and strength 2 times a week14	Anything your oncology team told you to watch for; tell them before you start a program14
Long COVID or ME/CFS with PEM	Pace: find a level that doesn’t trigger a crash, and rest before you’re spent515	Increase only after several stable days, and in small steps	A flare 12 to 48 hours after activity means cut back5

How strong is the evidence?

Claim	Evidence rating	What it rests on
The “neck check” tells you when exercise is safe with a cold	Not enough evidence	Expert advice; no studies cited12
Athletes without heart symptoms after COVID-19 can return gradually without heart tests	Promising but early	Expert consensus backed by registry data34
Ten days of bed rest saps strength and fitness in healthy older adults	Promising but early	One small, tightly controlled study from one team, plus its earlier report910
Exercise before surgery lowers complications	Promising but early	Small trials, low to moderate certainty1112
Exercise eases fatigue, anxiety and depression during and after cancer treatment	Strong evidence	An expert panel’s review of a large, fast-growing body of trials1314
Graded exercise therapy, with fixed step-ups, is a proven and safe ME/CFS treatment	Evidence says no, or unsafe	NICE judged the trials low or very low quality and says not to offer it; CDC warns standard exercise advice can harm people with ME/CFS; some UK medical bodies disagree567
Pacing improves ME/CFS symptoms	Not enough evidence	Five studies, two randomized; no clear benefit yet8

Questions readers ask

The bottom line

There’s no single rule for exercise after illness. A mild cold usually allows easy movement. Flu and COVID-19 call for rest through the fever and attention to chest symptoms. After a hospital stay, get moving soon, because bed rest takes strength fast.

Cancer survivors do better avoiding inactivity, with a plan their care team approves. With ME/CFS and long COVID that brings PEM, the safest path is the reverse of “push through”: pace yourself, protect your energy and build slowly.

Related reading

• The first 10 minutes of exercise pay off most, so start slower than you think
• A trainer coaches your squat while a physical therapist treats what hurts
• Frail 90-year-olds nearly tripled their strength, proof that muscle responds at any age
• Most back pain fades on its own, and dizziness and bladder leaks respond to rehab
• A doctor swallowed bacteria to prove a point, and consensus still took a decade

Sources

1. Mayo Clinic Staff. “Exercise and illness: Should you work out with a cold?” Mayo Clinic Care Network content via Mosaic Life Care, accessed October 2026. mymlc.com
2. South Dakota Department of Health. “Is it OK to exercise if I have a cold?” HealthySD.gov, accessed October 2026. healthysd.gov
3. American College of Cardiology. “2022 ACC Expert Consensus Decision Pathway on Cardiovascular Sequelae of COVID-19 in Adults: Key Points” (on Gluckman TJ, Bhave NM, Allen LA, et al., Journal of the American College of Cardiology, 2022). ACC, March 2022. acc.org
4. UW Medicine. “New advice on young athletes’ post-COVID return to play.” University of Washington, March 15, 2022. newsroom.uw.edu
5. Centers for Disease Control and Prevention. “Manage Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.” CDC, reviewed May 10, 2024. cdc.gov
6. Vink M, Vink-Niese A. “The Updated NICE Guidance Exposed the Serious Flaws in CBT and Graded Exercise Therapy Trials for ME/CFS.” Healthcare, 2022;10:898. mdpi-res.com
7. Tuller D. “Trial By Error: Losers in NICE Guideline Fight Remain Defiant Despite Public Repudiation of Their Claims.” Virology Blog, October 31, 2021. virology.ws
8. Sanal-Hayes NEM, Mclaughlin M, Mair JL, et al. “‘Pacing’ for management of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): a systematic review and meta-analysis.” Fatigue: Biomedicine, Health & Behavior, 2024 (University of Salford repository). salford-repository.worktribe.com
9. Kortebein P, Symons TB, Ferrando A, et al. “Functional impact of 10 days of bed rest in healthy older adults.” Journals of Gerontology Series A, 2008;63(10):1076-1081 (University of Texas Medical Branch record). researchexperts.utmb.edu
10. University of Arkansas for Medical Sciences. “Extended Bed Rest Accelerates Muscle Deterioration in Older Adults, UAMS Researchers Report in JAMA” (on Kortebein P, et al., JAMA, 2007;297(16):1772-1774). UAMS, April 25, 2007. news.uams.edu
11. Guerra-Londono CE, Cata JP, Nowak K, Gottumukkala V. “Prehabilitation in Adults Undergoing Cancer Surgery: A Comprehensive Review on Rationale, Methodology, and Measures of Effectiveness.” Current Oncology, 2024;31(4):2185-2200 (DOAJ record). pubmed.ncbi.nlm.nih.gov
12. Widanage N, Almonib A, Gunathilaka K. “The Effects of Multimodal Prehabilitation on Postoperative Outcomes in Colorectal Surgery: A Systematic Review and Meta-Analysis.” Cureus, 2025;17(10):e95032 (West Midlands repository record). westmid.openrepository.com
13. ecancer. “New international exercise guidelines for cancer survivors” (on Campbell KL, et al., Medicine & Science in Sports & Exercise, 2019). October 17, 2019. ecancer.org
14. Breastcancer.org. “Experts Update Exercise Guidelines for People Treated for Cancer.” October 23, 2019. breastcancer.org
15. Emerge Australia. “Stop, Rest, Pace” fact sheet. Health Translations, State Government of Victoria, published December 2025, reviewed July 2026. healthtranslations.vic.gov.au