How to Avoid Post-Exertional Malaise

Ever pushed through a hard workout and then felt wiped out for the next two days? That workout cost you more than it gave back. If you live with long COVID, POTS or MCAS, that crash has a name, post-exertional malaise, and Chinese medicine explains why it keeps happening. Avoiding it starts with thinking about what your body actually needs.

What is post-exertional malaise?

Post-exertional malaise, or PEM, is the crash that follows exertion: physical, mental or emotional. It is one of the things that keeps people with chronic illnesses like long COVID, POTS and MCAS from feeling like they can ever get better and go back to a normal life.

It is also one of the most common. The Patient-Led Research Collaborative surveyed 3,762 people with long COVID in 56 countries. After six months, post-exertional malaise was among the three most frequent symptoms, alongside fatigue and cognitive problems, and 85.9 percent had relapses, triggered mainly by exercise, physical or mental activity and stress.^[1]

How PEM turns into learned helplessness

This quickly turns into learned helplessness. Every crash teaches you that moving is dangerous, so you put walls around yourself. You stop walking, cancel plans and make your life smaller to stay safe. Those walls reinforce behaviors that are actually keeping you sick.

Research on chronic fatigue syndrome points to the same walls. In a planned analysis of the PACE trial, 641 people from six specialist clinics in the UK, the strongest driver of improvement with both graded exercise and cognitive behavior therapy was a drop in fear avoidance beliefs, and the effect was larger for graded exercise.^[2] Taking those walls down safely is a big part of what we do inside Gut Brain Synchrony.

Pacing for chronic fatigue: why do setbacks keep happening?

The evidence is very clear that graduated increases in activity are one of the best ways out of chronic fatigue syndrome. A Cochrane review pooled eight randomized trials with 1,518 participants. Compared with usual care or passive therapies, exercise therapy reduced fatigue at the end of treatment across seven trials and 840 people.^[3]

But for many people, they just keep encountering setbacks. They do a little more, crash, and retreat behind the walls again. Chinese medicine explains why. Graduated activity only works when you can see the edge before you go over it, and that means understanding what exertion is doing to your qi.

A body stuck in fight or flight also recovers differently from an athlete’s body. Valley Health Clinic’s guide to exercise for chronic pain and fatigue walks through why.

What causes post-exertional malaise?

In these situations, PEM is caused by irregular production and distribution of a signaling gas called nitric oxide. Nitric oxide is made by the cells lining your blood vessels and tells those vessels to open, so blood and oxygen reach the tissues that are working.

A 2022 study led from Austria and Chile grew human endothelial cells in plasma from 11 people with ME/CFS or 12 healthy controls. Cells bathed in ME/CFS plasma made less nitric oxide, both at rest and when stimulated by bradykinin, acetylcholine and histamine, the same messenger mast cells release in MCAS. The enzyme that makes nitric oxide was held in a more switched-off state.^[4]

The same pattern shows up after COVID. In 73 people hospitalized with COVID-19, flow-mediated dilation, the ability of an artery to widen when blood flow rises, was 1.65 percent against 6.51 percent in matched controls. It improved, but six months after discharge it was still impaired.^[5]

Qi and the Goldilocks zone

In Chinese medicine, we call this qi, and it has to be in a Goldilocks zone for your body to work right. Too little, too much, or poor distribution makes you sick. The classics name all three: deficiency, excess and stagnation, where qi may be plentiful but never reaches where it is needed.

Nitric oxide follows the same rule. Too little and vessels do not open. Too much is a problem too: biochemist Martin Pall proposed that elevated nitric oxide and its oxidant product, peroxynitrite, drive a self-sustaining cycle in chronic fatigue syndrome, fibromyalgia and multiple chemical sensitivity.^[6] Exercise pushes production up on purpose. Nitric oxide helps open skin vessels to shed heat during endurance work, and excessive exercise tips into high oxidative stress that impairs cardiovascular function.^[7] A body that cannot regulate its qi overshoots, or runs out.

Why am I so tired the day after exercise?

Because PEM usually lands 12 to 48 hours after activity. So you end up blaming your sleep from the night before, or the walk from earlier that morning, but it could have been something you did two full days ago or even more.

At Stanford, 150 people with chronic fatigue syndrome described their own crashes. Onset and duration varied, but 11 percent reported a consistent delay of at least 24 hours before PEM began, and 84 percent endured it for 24 hours or more.^[8]

In the largest two-day exercise test study yet, 84 people with ME/CFS and 71 sedentary controls did a maximal cycling test, then repeated it 24 hours later. Controls matched their first result. The ME/CFS group could not: work, exercise time, oxygen use and heart rate all fell on day two. The decline held when patients were matched to controls for fitness, so it was not about being out of shape. The authors pointed to autonomic dysregulation of blood flow and oxygen delivery.^[9] The bill for day one came due on day two.

The next time you crash, look at your activity from the previous week. A crash on Thursday may belong to Monday.

Post-exertional malaise symptoms: the four early warning signs

Before a crash, your body sends very subtle signals that your qi is headed toward a cliff. These are the four signs.

1. Sweating earlier than you normally would

In Chinese medicine, protective qi holds the pores closed. When qi is straining, it cannot hold, and sweat comes early and easily. Physiology tells a matching story: nitric oxide takes part in the vessel opening that drives heat loss during exercise.^[7]

2. Yawning while you’re moving around

Yawning is not only about being sleepy. It is one way the body cools the brain. In a study of 120 pedestrians, 41.7 percent reported yawning in summer against 18.3 percent in winter, and temperature was the only significant predictor.^[10] The Lingshu describes yawning as yin and yang pulling against each other. Yawning in the middle of a walk means regulation is under strain.

3. Weakness or heaviness in the legs and lower body

When qi cannot reach the lower body, the legs feel weak, heavy or hard to lift. In Chinese medicine the Spleen governs the muscles of the limbs and the Kidneys anchor the lower body, so heavy legs mean the foundation is running low.

4. A sudden episode of dizziness or brain fog

When qi fails to rise to the head, the head goes light or cloudy. In a survey of 138 people with POTS, 132 reported brain fog. The most common triggers were fatigue (91 percent), prolonged standing (87 percent) and feeling faint (85 percent).^[11] If this is your picture, read Does POTS Go Away on Its Own?

Qigong for chronic fatigue syndrome

Start adding slow breathing and qigong into your daily routine so it can pull your nervous system off high alert and give your body time to repair. This also builds awareness of those four subtle signs, so you know when to rest before triggering PEM.

Slow breathing takes the nervous system off high alert

A 2022 meta-analysis of 223 studies found that slow breathing raises vagally mediated heart rate variability, the marker of rest-and-repair activity, during the practice, right after a single session, and after a program of several sessions.^[12]

Qigong lowers fatigue in chronic fatigue and long COVID

In a Hong Kong trial, 137 people with chronic fatigue syndrome-like illness were randomized to qigong or a waitlist. Ten classes over five weeks and twelve weeks of home practice significantly improved total fatigue, physical fatigue and depression.^[13] A 2024 meta-analysis of 13 randomized trials and 661 people with chronic fatigue or post-COVID syndrome found that qigong, tai chi and yoga reduced fatigue and also improved anxiety, depression and sleep.^[14]

Qigong builds awareness

Qigong trains you to feel qi, and that same attention is what catches the four signs early. At UC Davis, 26 people with long COVID took six weekly qigong sessions. Ninety-two percent reported feeling qi, and about three-quarters improved in one or more symptoms, most often fatigue, brain fog and sleep quality.^[15] New to it? Start with the best qigong exercises for beginners, or try The Ultimate Warm-Up for a gentle warm-up of shaking, patting, stretching and breathing.

How to avoid post-exertional malaise

If PEM is part of a bigger picture of POTS, MCAS or chronic infection, start with Lyme Disease: Start Here.

Post-exertional malaise: your questions

How long does post-exertional malaise last?

It usually lands 12 to 48 hours after activity, and it tends to linger. In the Stanford survey, 84 percent of people with chronic fatigue syndrome endured PEM for 24 hours or more.

What are the symptoms of post-exertional malaise?

Fatigue is the most common, along with brain fog, poor sleep, headaches, muscle pain and flu-like feelings. Before the crash, watch for the four early signs.

Does exercise help with POTS?

Graduated increases in activity are one of the best ways out. The key is to keep your qi in the Goldilocks zone: build slowly, watch for the four signs, and rest before you trigger PEM.

Give your body what it actually needs, and your next workout can give back more than it costs.

— Brehan Crawford, L.Ac.

References

1. Davis HE, Assaf GS, McCorkell L, et al. Characterizing long COVID in an international cohort: 7 months of symptoms and their impact. EClinicalMedicine. 2021;38:101019. doi:10.1016/j.eclinm.2021.101019
2. Chalder T, Goldsmith KA, White PD, Sharpe M, Pickles AR. Rehabilitative therapies for chronic fatigue syndrome: a secondary mediation analysis of the PACE trial. Lancet Psychiatry. 2015;2(2):141-152. doi:10.1016/S2215-0366(14)00069-8
3. Larun L, Brurberg KG, Odgaard-Jensen J, Price JR. Exercise therapy for chronic fatigue syndrome. Cochrane Database Syst Rev. 2024;12(12):CD003200. doi:10.1002/14651858.CD003200.pub9
4. Bertinat R, Villalobos-Labra R, Hofmann L, Blauensteiner J, Sepúlveda N, Westermeier F. Decreased NO production in endothelial cells exposed to plasma from ME/CFS patients. Vascul Pharmacol. 2022;143:106953. doi:10.1016/j.vph.2022.106953
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9. Keller B, Receno CN, Franconi CJ, et al. Cardiopulmonary and metabolic responses during a 2-day CPET in myalgic encephalomyelitis/chronic fatigue syndrome: translating reduced oxygen consumption to impairment status to treatment considerations. J Transl Med. 2024;22(1):627. doi:10.1186/s12967-024-05410-5
10. Massen JJM, Dusch K, Eldakar OT, Gallup AC. A thermal window for yawning in humans: yawning as a brain cooling mechanism. Physiol Behav. 2014;130:145-148. doi:10.1016/j.physbeh.2014.03.032
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12. Laborde S, Allen MS, Borges U, et al. Effects of voluntary slow breathing on heart rate and heart rate variability: a systematic review and a meta-analysis. Neurosci Biobehav Rev. 2022;138:104711. doi:10.1016/j.neubiorev.2022.104711
13. Chan JSM, Ho RTH, Wang CW, Yuen LP, Sham JST, Chan CLW. Effects of qigong exercise on fatigue, anxiety, and depressive symptoms of patients with chronic fatigue syndrome-like illness: a randomized controlled trial. Evid Based Complement Alternat Med. 2013;2013:485341. doi:10.1155/2013/485341
14. Fricke-Comellas H, Heredia-Rizo AM, Casuso-Holgado MJ, Salas-González J, Fernández-Seguín LM. Exploring the effects of qigong, tai chi, and yoga on fatigue, mental health, and sleep quality in chronic fatigue and post-COVID syndromes: a systematic review with meta-analysis. Healthcare (Basel). 2024;12(20):2020. doi:10.3390/healthcare12202020
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