Exercise When Blood Counts Are Low: What to Ask

A complete blood count, or CBC, measures several things at once. When treatment knocks the numbers down, people say their counts are low, as if it were one condition. It is not. Three separate cells fail in three separate ways, and each one changes exercise differently.

• White cells, especially neutrophils, fight infection. Low neutrophils change where you exercise and who is around you.
• Platelets stop bleeding. Low platelets change what you do, mainly by ruling out things that can cause a blow or a fall.
• Red cells carry oxygen. Low red cells change how hard you can work.

Ask which one is low before changing anything. The answer points to a different fix each time.

Neutrophils are the white cells that fight bacteria. The absolute neutrophil count, or ANC, comes out of the CBC. St. Jude gives the bands: above 1,500 is normal for a healthy child, 1,000 to 1,500 is mild neutropenia, 500 to 1,000 is moderate, below 500 is severe, and below 100 is profound. The lower the number, the higher the risk, and even a minor infection can turn serious.

Notice what is not on that list: exertion. Walking hard does not lower your ANC. The danger is exposure.

So change the setting, not the workout:

• Move it home, or go to the gym at its emptiest hour.
• Wipe equipment before and after, and wash your hands before you touch your face or eat.
• Skip crowds and stay away from anyone who is sick. NCI names both in its infection prevention advice.
• The American Cancer Society advises avoiding swimming during treatment.
• Take outdoor walks. Open air is one of the lowest-risk places to move.

The fever rule does not change because you exercised. NCI advises calling the care team for a temperature of 100.5 °F (38 °C) or higher. St. Jude uses a single oral reading of 100.9 °F (38.3 °C), or 100.4 °F (38.0 °C) held for an hour. Use your team's exact number, and do not assume a post-workout flush explains it.

Here is where most articles invent a number. This one will not.

NCI's guidance for people with low platelets is about avoiding injury, and it does not name a platelet count at which exercise must stop. The federal Physical Activity Guidelines do not name one either. Individual cancer centers do use internal cutoffs, and those numbers are not the same from center to center.

So the number that governs you is your team's number, and you have to ask for it. Use these words:

• At what platelet count do you want me to stop resistance training?
• At what count should I avoid anything with fall or impact risk?
• At what count should I stop exercising and rest?
• My counts are drawn weekly. What do I do on the days in between, when I do not know today's number?
• Am I on a blood thinner or any medicine that adds to bleeding risk?

Some choices make sense at any low count, because they carry a real chance of a blow or a fall: contact sports, downhill skiing, mountain biking, ladders, and heavy lifts where you hold your breath and strain. Swap them for walking, a stationary bike, bodyweight work at lighter effort, or bands.

NCI's other low-platelet advice matters around exercise too. Avoid products containing aspirin or ibuprofen, and limit alcohol. Brush with a very soft toothbrush. Wear shoes even indoors. Use an electric shaver instead of a razor. Be careful with sharp objects. If bleeding starts, press firmly on the spot with a clean cloth and keep pressing until it stops.

Watch for the bleeding signs NCI lists: bleeding that does not stop after a few minutes, bleeding from the mouth or nose or in vomit, urine that is red or pink, stools that are black or bloody, periods heavier or longer than usual, and bad headaches or changes in vision.

Anemia means the red cell count is below normal, so less oxygen reaches your muscles. NCI lists the symptoms: extreme fatigue, shortness of breath, lightheadedness, dizziness, fainting, headache, fast heartbeat, and pale skin.

The instinct is to rest completely. NCI advises against that. Its guidance is to balance rest with activity, allow short naps, and remember that too much bed rest makes you weak. It also says to take short walks or exercise a little every day.

Practical translation:

• Cut intensity before you cut the habit. A 10-minute easy walk beats a skipped 30-minute one.
• Use the talk test. If you cannot speak a full sentence, ease off.
• Break it up. Three 10-minute walks count the same as one 30-minute walk.
• Stand up slowly from the floor or a bench, and hold something.
• Sit down to lift. Seated exercises remove the dizziness risk.
• Stop for chest pain, fainting, or breathlessness that does not settle within a few minutes of rest.

None of this means stopping. NCI reports that exercise training and testing are generally safe for cancer survivors, and that aerobic or resistance training during and after treatment can reduce anxiety, depressive symptoms, and fatigue while improving quality of life and physical function.

The Physical Activity Guidelines for Americans set the adult target at 150 to 300 minutes a week of moderate activity, plus muscle-strengthening work on at least 2 days. For adults with chronic conditions, the guidelines say to be as physically active as your abilities allow, to avoid inactivity, and to be under the care of a health care provider. NCI's summary of the ACSM roundtable gives a workable dose: about 30 minutes of aerobic exercise three times a week, plus resistance training twice a week.

On a low-count week, the goal is to keep the habit alive at a smaller size, so you are not starting over when the numbers recover.

• Which count is low, what is the actual number, and when is it expected to recover?
• What is your cutoff for stopping resistance training, and for stopping exercise?
• Do I have any bone involvement that changes what is safe?
• Do I have a port or central line that limits certain movements?
• Would you refer me to a physical therapist or cancer rehabilitation program?
• Should I check my heart rate or blood pressure before exercising?

Stop and call the care team the same day for:

• Bleeding that will not stop after 10 minutes of firm pressure.
• Black or bloody stools, or red or pink urine.
• A severe headache, confusion, or a change in vision.
• Fainting, chest pain, or breathlessness at rest.
• A fever at your team's threshold, which for many centers is a single reading of 100.9 °F (38.3 °C), or 100.4 °F (38.0 °C) lasting an hour.

Go to an emergency department after any fall with a head strike while your platelets are low, even if you feel fine.

See Low Platelets During Chemotherapy, Low White Blood Cells During Chemotherapy, and Neutropenia During Chemotherapy for the counts themselves. See Neutropenic Fever During Cancer Treatment for the emergency plan. Also useful: Stretching After Cancer Surgery: What to Ask and Breathing and Relaxation Before Cancer Appointments.

• Bleeding and Bruising (Thrombocytopenia) and Cancer Treatment, National Cancer Institute
• Anemia and Cancer Treatment, National Cancer Institute
• Infection and Neutropenia during Cancer Treatment, National Cancer Institute
• Physical Activity and Cancer Fact Sheet, National Cancer Institute
• Prescribing Exercise as Cancer Treatment, National Cancer Institute
• Physical Activity Guidelines for Americans, 2nd edition (PDF), U.S. Department of Health and Human Services
• Absolute Neutrophil Count (ANC) and Neutropenia, Together by St. Jude
• Fever and Signs of Infection, Together by St. Jude
• ACS Nutrition and Physical Activity Guideline for Cancer Survivors, American Cancer Society