How to Lower Red Blood Cell Count Naturally

Elevated red blood cell counts, a condition broadly called polycythemia, can often be nudged downward through lifestyle changes before medical interventions like therapeutic phlebotomy become necessary. Staying well hydrated, quitting smoking, exercising regularly, and adjusting certain dietary habits are the strategies with the most evidence behind them. How much each one helps depends on why your count is high in the first place, and some causes require medical treatment no matter what you do at home.

Why Your Red Blood Cell Count Might Be High

Before trying to lower your count, it helps to understand what is driving it up. Red blood cell production is governed by erythropoietin, a hormone made primarily by the kidneys in response to low oxygen levels in the blood.¹ Anything that chronically lowers your blood oxygen, from smoking to living at high altitude to untreated sleep apnea, can push the kidneys to produce more erythropoietin and, in turn, more red blood cells.

There is also a distinction between a genuinely elevated red cell mass and a falsely elevated count caused by low plasma volume. When you are dehydrated, for example, your blood becomes more concentrated and your hematocrit (the percentage of blood that is red blood cells) rises, even though you have not actually made more red cells. Doctors can differentiate between these two situations by measuring red cell mass and plasma volume directly.² This matters because the fix for dehydration-driven high readings is very different from the fix for a bone marrow disorder cranking out too many cells. Most of the natural strategies below work either by expanding your plasma volume, by removing the stimulus that is driving overproduction, or by reducing iron availability for new red cell manufacturing.

Drink More Water and Stay Hydrated

This is the simplest and fastest-acting intervention. When your fluid intake drops, your plasma volume shrinks and your hematocrit climbs, sometimes meaningfully. A study of young men cycling in hot conditions found that exercising without any hydration caused significantly higher hemoglobin and hematocrit values compared to drinking water, and water in turn produced higher readings than an isotonic sports drink. An hour after exercise, the group that drank nothing still had elevated hematocrit, while the isotonic drink group actually showed an increase in plasma volume above baseline.³

Even outside of exercise, simply drinking water can move the needle. In a study of patients with diabetes, oral water hydration significantly lowered average hematocrit values.⁴ If your elevated count is partly driven by chronic mild dehydration, which is more common than most people realize, especially in older adults or people who rely on coffee and alcohol as their main fluids, consistent water intake alone may bring your numbers into a healthier range. This will not fix a genuinely elevated red cell mass, but it is the right first step for anyone whose readings are borderline.

Quit Smoking

Smoking raises red blood cell counts through a straightforward mechanism: carbon monoxide in cigarette smoke binds to hemoglobin and reduces the blood’s ability to carry oxygen. Your kidneys detect the lower oxygen delivery and respond by signaling for more red cell production. The result is a chronically elevated hematocrit that can persist as long as the habit does.

A study of polycythemic patients found that those who quit smoking had significantly lower hemoglobin and hematocrit values within three months compared to their baseline. Smokers in the study had higher hemoglobin at baseline than non-smokers, and the decline after quitting was large enough that researchers noted it could reduce the need for phlebotomy and lower the risk of serious complications like blood clots.⁵ Three months is a realistic timeline for the effect to show up on lab work, though some improvement begins sooner as carbon monoxide levels in the blood drop within days of quitting.

If you smoke and your blood work shows elevated red cells, this is probably the single highest-impact change you can make. No amount of hydration or dietary adjustment will overcome the daily oxygen debt that smoking creates.

Exercise Regularly

Regular exercise lowers your effective red blood cell concentration by expanding plasma volume, the liquid portion of your blood. After a hard workout, your body retains more fluid in the bloodstream over the next day or so, diluting your red cells even though the total number has not changed. One study found that a single session of intense intermittent exercise expanded plasma volume by roughly ten percent within 24 hours.⁶ Another study confirmed that high-intensity interval training expanded plasma volume by about six to seven percent the day after exercise, regardless of whether participants ran on a treadmill or used a stationary bike.⁷

People who exercise consistently maintain a chronically expanded plasma volume, which is one reason endurance athletes often have hematocrit values in the low-normal range even though their total red cell mass may actually be above average. If your doctor sees a mildly elevated hematocrit and you are sedentary, adding regular cardio may be enough to tip the balance. You do not need extreme training, though the plasma-volume effect is most pronounced with vigorous exercise. Even moderate-intensity sessions done consistently will produce some expansion over time.

Manage Iron Intake Through Diet

Iron is a raw material for hemoglobin, and your body’s ability to make new red blood cells depends partly on how much iron is available. You do not want to become iron deficient, which brings its own problems, but if your red cell count is already elevated, you also do not want to be loading up on iron-rich foods and supplements that give your bone marrow extra building material.

One practical approach involves the timing and pairing of meals with beverages that naturally reduce iron absorption. Polyphenol-rich drinks like tea, coffee, cocoa, and certain herbal teas are potent inhibitors of non-heme iron absorption. In a study measuring iron uptake from a bread meal, beverages with higher polyphenol content reduced absorption by 60 to 90 percent, while even those with modest polyphenol content cut absorption roughly in half.⁸ The effect was dose-dependent: more polyphenols meant less iron absorbed. Coffee, black tea, peppermint tea, and cocoa all showed strong inhibitory effects.

This does not mean you should drink tea with every meal if your iron levels are already normal or low. But if your ferritin and hemoglobin are both elevated, drinking a cup of tea or coffee alongside iron-rich meals is a simple strategy that limits how much new iron your gut takes in. Conversely, avoiding vitamin C-rich foods and drinks at the same time as iron-heavy meals can also reduce absorption, since vitamin C is one of the strongest enhancers of non-heme iron uptake. Heme iron, the kind found in red meat and organ meats, is less affected by these dietary inhibitors, so cutting back on those foods directly is more effective if you are trying to restrict iron supply at the source.

The Grapefruit Effect

A more surprising dietary finding involves grapefruit. A study of 36 people found that eating half a grapefruit or one whole grapefruit daily for 42 days significantly lowered hematocrit in those who started with elevated levels. The highest starting hematocrits dropped the most, while those who began with low hematocrits actually saw a slight increase. There was no significant difference between eating half versus a whole grapefruit per day.⁹

The proposed mechanism centers on naringin, a flavonoid in grapefruit that appears to cause red blood cells to clump together, making them more likely to be cleared from circulation by immune cells. The self-correcting nature of the effect is interesting: it lowered high hematocrits without making low ones worse, suggesting it acts more like a regulator than a blunt-force suppressor. One important caveat: grapefruit interacts with a long list of medications, including certain blood thinners and statins. If you are on any prescription drugs, check with your pharmacist before adding daily grapefruit to your routine.

Treat Sleep Apnea

Obstructive sleep apnea causes repeated drops in blood oxygen throughout the night, and over time your body compensates by producing more red blood cells. Treating the apnea removes that oxygen stimulus and lets your count drift back down. In a study of patients starting CPAP therapy, hematocrit dropped from an average of about 45.6% to 43.0% essentially overnight, with a parallel drop in red blood cell count. The researchers attributed this rapid change to a fluid shift rather than a change in production, essentially a hemodilution effect triggered by the restoration of normal breathing.¹⁰

Over weeks and months of consistent CPAP use, the longer-term suppression of erythropoietin contributes to a sustained reduction in red cell production. If you have been told your red cell count is high and you snore heavily, wake up gasping, or feel exhausted despite sleeping enough hours, undiagnosed sleep apnea may be the culprit. Getting a sleep study could address both problems at once.

Reduce Chronic Stress

Acute mental stress produces a small but measurable spike in hematocrit. Research tracking blood samples every one to two minutes during a stress task found that hematocrit rose by about 1.3% during just four minutes of mental stress, and it took roughly 16 to 20 minutes of recovery before returning to baseline.¹¹ ¹² The mechanism appears to involve a stress-driven shift of fluid out of blood vessels and into surrounding tissue, concentrating whatever red cells are already there.

A 1.3% bump from a single episode sounds small, but chronic stress means these spikes happen repeatedly throughout the day, and people under sustained stress tend to carry a slightly higher baseline hematocrit as a result. More critically, stress-induced hemoconcentration has been flagged as a possible contributor to acute cardiovascular events, because thicker blood is more prone to clotting. Stress management will not dramatically lower a genuinely elevated red cell count, but for someone whose hematocrit consistently comes back borderline-high, chronic stress may be padding the number.

What Happens When You Come Down From Altitude

People who live or train at high altitude develop elevated red blood cell counts as an adaptation to lower oxygen levels. When they descend to lower elevations, the body needs to shed those extra cells, and it does so through a process called neocytolysis: the selective destruction of the youngest red blood cells in circulation.¹³ The drop in erythropoietin that comes with re-oxygenation triggers this cleanup. In one study of climbers descending from high altitude, erythropoietin levels fell dramatically, and young and middle-aged red blood cells largely disappeared from circulation within six days.¹⁴

The mechanism behind neocytolysis is rooted in how red cells formed under low-oxygen conditions are uniquely vulnerable once oxygen levels normalize. These cells have lower antioxidant defenses and higher mitochondrial activity, so when oxygen suddenly becomes abundant again, they sustain more damage from reactive oxygen species and are flagged for destruction.¹⁵ If you have been living or spending extended time at elevation and your blood work shows a high count, simply returning to a lower altitude will initiate a natural correction that unfolds over days to weeks.

Why Elevated Red Cell Counts Matter

The urgency behind lowering your count depends on how high it is and what risks it carries. Thick, concentrated blood flows less easily and is more prone to clotting. A large population study found that for every five-percentage-point increase in hematocrit, the risk of venous blood clots rose by about 25 percent overall and by about 37 percent for clots that occurred without an obvious provocation like surgery or immobilization. Men whose hematocrit was in the top fifth of the distribution faced roughly 2.4 times the risk of unprovoked clots compared to those in the bottom two-fifths.¹⁶

These numbers help explain why doctors take persistently elevated hematocrit seriously and why they may recommend phlebotomy, which is essentially therapeutic blood donation, for people whose levels are high enough to warrant concern. When apheresis devices are used in clinical settings to selectively remove red blood cells from patients with high ferritin levels, hematocrit drops of five to seven percentage points per session are typical.¹⁷ Regular blood donation through a standard blood bank, where you are eligible, serves a similar purpose and can be a reasonable maintenance strategy if your doctor agrees the levels are high enough to benefit from periodic removal but not so high that they require medical phlebotomy on a set schedule.

When Natural Approaches Are Not Enough

Lifestyle changes work best when the cause of your elevated count is something modifiable: dehydration, smoking, sedentary habits, untreated sleep apnea, or living at altitude. They are less likely to be sufficient for polycythemia vera, a bone marrow disorder where the body produces red cells regardless of oxygen or erythropoietin levels, or for secondary polycythemia driven by a tumor that secretes erythropoietin. Testosterone replacement therapy is another common cause of elevated red cell counts that may require dose adjustments under medical supervision rather than home remedies.

If your hematocrit consistently runs above about 50% in men or 45% in women despite reasonable hydration and no obvious lifestyle triggers, your doctor will likely want to investigate further. In the meantime, the lifestyle interventions described here, particularly hydration, smoking cessation, and exercise, are worth pursuing regardless of the underlying cause. They improve overall cardiovascular health, they will not make the problem worse, and in many cases they are genuinely the only treatment needed.

How Tibetans Evolved a Different Solution

For a fascinating window into how the human body can solve the problem of too many red blood cells, consider Tibetans. Populations that have lived on the Tibetan Plateau for thousands of years have evolved genetic variants that keep their hemoglobin levels relatively low despite living at altitudes where most people’s counts would climb significantly. Several of these variants sit in or near genes involved in oxygen sensing, including EPAS1, EGLN1, and PPARA.¹⁸

The EPAS1 gene is particularly well studied. In Tibetans carrying the adaptive version, EPAS1 expression under low-oxygen conditions is roughly 30 percent lower than in people carrying the standard version.¹⁹ Because EPAS1 is a key player in the signaling cascade that ramps up red blood cell production in response to low oxygen, dialing it down means Tibetans do not overshoot the way most lowlanders do when they move to altitude. The result is a population that thrives at extreme elevations without the dangerously thick blood that afflicts newcomers. Chronic mountain sickness, which is essentially altitude-driven polycythemia, is far less common in Tibetans than in other high-altitude populations that have not had as many millennia to adapt. It is a reminder that the body’s red blood cell production system was not designed for a fixed output: it is flexible, responsive to signals, and in many cases, amenable to the kind of signal changes that lifestyle modifications provide.