Factors That Affect
Note: According to published cardiovascular research, factors that raise resting heart rate include: caffeine, stress, dehydration, fever, medications, and poor sleep. Factors that lower it include: regular cardio exercise, adequate sleep, good hydration, and relaxation practices. Resting Heart Rate
Many variables influence RHR independently of age or fitness:
Fitness Level
Regular aerobic exercise (running, cycling, swimming) lowers RHR over weeks to months. Elite endurance athletes often achieve rates of 30–40 bpm.[^3] Even moderate activity (30 minutes of brisk walking, 5×/week) can lower RHR by 5–10 bpm over 8–12 weeks.
Mechanism: Aerobic training increases stroke volume (the volume of blood the heart pumps per beat), allowing it to meet oxygen demands with fewer beats.
Stress and Mental State
Psychological stress and anxiety chronically elevate RHR. During stressful periods, cortisol and adrenaline increase, raising baseline HR. Relaxation, meditation, and yoga reduce RHR.[^4] Understanding how stress affects your body explains the physiological mechanisms behind this elevation; the burnout quiz helps identify whether chronic stress or burnout may be affecting your baseline heart rate.
A person's typical RHR might be 68 bpm, but during a stressful work week, it could be 75–80 bpm.
Caffeine Intake
Caffeine is a stimulant that increases heart rate acutely. A cup of coffee (95–200 mg caffeine) can raise RHR by 5–10 bpm for 3–5 hours.
Implication: Measure RHR before caffeine consumption for consistency. Measure morning RHR immediately upon waking, before coffee.
Medications
Many prescription medications affect heart rate:
- Beta-blockers (for hypertension, anxiety): lower HR
- Decongestants (pseudoephedrine): raise HR
- Stimulants (ADHD medications): raise HR
- Thyroid medications: can raise HR if dosed too high
Inform your healthcare provider if RHR changes significantly after starting medication.
Temperature and Environment
Heat increases HR as the cardiovascular system works to cool the body. Cold exposure temporarily increases HR (thermogenesis). Altitude (high elevation with lower oxygen) also elevates RHR.
Consistency: Measure RHR in a temperature-controlled room at sea level for consistency.
Dehydration
Dehydration reduces blood volume, forcing the heart to beat faster to maintain adequate circulation. Even 2–3% fluid loss can elevate RHR by 5–10 bpm.
Ensure adequate hydration (especially before measuring) for accurate baseline RHR.
Illness and Infection
Fever, cold, flu, or other illness elevates RHR as the body's immune system activates. RHR typically returns to baseline within days to weeks post-recovery.
Don't measure RHR during active illness; wait until fully recovered.
Hormonal Fluctuations
Women's RHR varies with menstrual cycle phases due to estrogen and progesterone shifts. RHR is typically lowest during the follicular phase (pre-ovulation) and slightly elevated during the luteal phase (post-ovulation).
This variation is normal (2–5 bpm) and not indicative of a problem.
Sleep Quality
Poor sleep elevates RHR. Chronic sleep deprivation (less than 6–7 hours) keeps the nervous system in a heightened state, raising baseline HR.
Improved sleep (7–9 hours) can lower RHR by 3–8 bpm over weeks.
Body Composition
Higher body fat percentage associates with slightly elevated RHR, as the heart must pump more to supply the larger body mass.[^1] Conversely, improved fitness (lower body fat, higher muscle mass) correlates with lower RHR.