Unexplained fatigue: The overlooked heart attack warning sign in women

The image of a heart attack is almost always the same: sudden, crushing chest pain, a hand clutching the left arm, an unmistakable emergency. But for many women, the warning comes differently—not as a thunderbolt, but as a creeping exhaustion that settles in days or even weeks before the heart actually fails. Cardiologists now recognize that this unexplained fatigue is among the most common precursors to a heart attack in women, appearing in as many as seven out of ten cases. Yet because fatigue is so ordinary, so easily explained away by the demands of modern life, both patients and doctors often miss it entirely.

The distinction matters enormously. Feeling worn out after a sleepless week or a stretch of demanding work is normal. What cardiologists like Arash Bereliani watch for is something different: a marked, unexplained drop in energy from whatever your baseline used to be. When blood flow to the heart begins to weaken, the heart muscle itself struggles to function efficiently. It cannot circulate enough oxygen-rich blood to the rest of the body, leaving muscles and organs starved of oxygen and nutrients. The result is an overwhelming sense of exhaustion that rest alone cannot fix.

The problem is that fatigue is perhaps the most common complaint a doctor hears, especially from women managing work, family, caregiving, and everything else that fills a life. Amy Ahnert, a cardiologist at Atlantic Medical Group and director of the Women's Heart Program at Morristown Medical Center, notes that so many women are juggling multiple roles simultaneously, stretched thin across competing demands. That reality makes it dangerously easy for both patients and physicians to dismiss a cardiovascular warning sign as just another symptom of being overextended. One large study of heart attack patients under 55 found that women were significantly more likely than men to interpret their symptoms as stress or anxiety. Many had already seen a doctor who failed to connect their complaints to their heart.

For decades, medical understanding of heart attacks was built almost entirely on research conducted in men. The classic presentation—chest pain or tightness radiating down the left arm—became the template against which all other symptoms were measured. Doctors assumed that women would simply experience the same signs. We now know that is not true. Women can have a much wider range of symptoms, though researchers are still working to understand exactly why. Anatomical differences play a role, including variations in heart size and how the nervous system responds when the heart is under stress. Inflammation appears to be involved as well; the plaque buildup that triggers many heart attacks is often accompanied by inflammation, and that inflammatory response seems to be associated with fatigue more commonly in women, though the mechanism remains unclear.

There is also a fundamental difference in the types of heart disease men and women tend to develop. Men more often suffer from obstructive coronary artery disease, in which plaque narrows or blocks one of the major arteries feeding the heart. Women are comparatively more likely to develop coronary microvascular disease, a condition affecting the heart's smallest blood vessels. These tiny vessels can become stiff or lose their ability to expand properly, limiting blood flow even when no major artery is completely blocked. Microvascular disease itself can cause fatigue and chest discomfort. In some cases, dysfunction in these small vessels can worsen over time and substantially reduce the blood supply to the heart. This may explain why some women experience more gradual or vague warning signs stretched over weeks rather than a single dramatic symptom that announces itself immediately.

Heart-related exhaustion feels fundamentally different from ordinary tiredness. As Ahnert describes it, the sensation is one of complete depletion: "I can't do anything. I have no energy. I'm weak, and I'm tired." Normal fatigue improves after a full night's sleep. Cardiovascular fatigue does not. Someone may sleep through the night and wake feeling just as exhausted as when they went to bed. Physical activity provides another crucial clue. A person who is merely tired can usually still accomplish ordinary daily tasks—walking their usual distance, climbing stairs. With heart-related fatigue, activities that were once effortless suddenly become overwhelming. Bereliani recalls one patient whose primary warning sign was an abrupt inability to hold her arms up long enough to blow-dry her hair. Duration matters too. Fatigue that persists for several days or weeks without an obvious cause deserves more attention than a brief spell of tiredness.

Concern should intensify when exhaustion appears alongside other possible cardiovascular symptoms. Chest pain remains the most common heart attack symptom overall, but women are more likely than men to have heart attacks without classic chest pain. Some experience pressure or discomfort rather than sharp pain. Others feel pain in the jaw, neck, or back. Doctors say unexplained fatigue becomes particularly worrisome when it occurs together with chest discomfort, jaw or neck pain, shortness of breath, nausea, vomiting, indigestion, sweating, sleep disturbance, dizziness, or lightheadedness. If fatigue is persistent, if it worsens with physical exertion, if it is accompanied by other symptoms, or if it does not improve within a few days, a doctor should be consulted. If fatigue becomes debilitating or occurs alongside a symptom that disrupts normal activity—severe shortness of breath, new upper-body pain, heavy sweating—emergency evaluation is necessary. In the United States, calling 911 is preferable to being driven to the hospital, since cardiac arrest or a dangerous abnormal heart rhythm can develop during transport. Ahnert emphasizes that women in particular tend to underestimate how serious their symptoms are, and that patients should trust their own sense that something is wrong, especially if doctors dismiss their concerns.