Blood pressure measures the force of blood against artery walls, typically given as a fraction (e.g., 120/80 mmHg). The top number, systolic pressure, measures force when the heart contracts. The bottom number, diastolic pressure, measures the force when the heart relaxes and refills with blood between beats. This diastolic number is particularly important because the heart muscle receives its own blood supply during this resting phase. Intense physical training significantly affects both measurements, often leading to readings that differ noticeably from the general population’s average.
Blood Pressure Readings Common in Athletes
Yes, athletes, particularly those engaged in high volumes of endurance training, generally have lower resting blood pressure readings. A typical healthy reading for the average adult is considered to be below 120/80 mmHg. Highly trained individuals often exhibit resting blood pressure that is significantly lower than this standard. For many athletes, blood pressure commonly falls within a range of 90–110 mmHg systolic and 50–70 mmHg diastolic. A diastolic reading in the range of 50 to 60 mmHg is frequently observed and considered a normal, healthy adaptation in this specific population. While these numbers might signal low blood pressure, or hypotension, in a sedentary person, they are often a sign of superior cardiovascular fitness in a well-conditioned athlete.
How Exercise Changes Diastolic Pressure
The consistently lower diastolic pressure in athletes is a direct result of profound cardiovascular adaptations caused by regular training. This process often leads to what is known as “Athlete’s Heart,” characterized by changes that improve the heart’s pumping efficiency. Regular, intense exercise strengthens the heart muscle, allowing it to pump a much greater volume of blood with each beat. This increased stroke volume means the heart does not need to beat as often at rest to maintain adequate circulation, which contributes to overall lower pressure.
A second mechanism involves changes in the peripheral circulatory system, mainly reduced systemic vascular resistance. Regular aerobic activity promotes the dilation and flexibility of blood vessels throughout the body. The blood vessels stay more relaxed and open, which lowers the resistance to blood flow. Since diastolic pressure is largely determined by this peripheral resistance, the increased flexibility and wider diameter of the arteries directly result in a lower pressure reading when the heart is between contractions.
The relaxation of the blood vessels is partly mediated by the increased production and release of substances like nitric oxide, which acts as a powerful vasodilator. This effect on the blood vessels ensures that blood can flow easily even with a lower force exerted by the heart during the resting phase. This combination of a more powerful, efficient heart and more compliant blood vessels establishes the lower resting diastolic pressure common in athletes.
Recognizing When Low Diastolic Pressure Is Too Low
While a low diastolic pressure is generally a sign of health in athletes, there is a point where it can become too low, even for a conditioned individual. For the general population, a reading below 60 mmHg is often a threshold for concern. When blood pressure is too low, it is referred to as hypotension, and it can become pathological if it causes symptoms.
The primary concern with overly low diastolic pressure is that it may compromise the blood flow to the heart muscle itself, which receives oxygenated blood during diastole. The adaptive low pressure becomes problematic when the body signals that organs are not receiving sufficient blood supply. Symptoms suggesting the low pressure is no longer an athletic adaptation include persistent dizziness, lightheadedness, or blurred vision.
Other warning signs are chronic fatigue, nausea, or episodes of fainting, especially when standing up quickly. If an athlete experiences these symptoms, particularly if they are new or interfere with training and recovery, they should consult a healthcare professional. A symptomatic low blood pressure reading requires medical evaluation to rule out underlying issues and ensure the low pressure is not causing inadequate perfusion to vital organs.