Possible causes
- Overtraining and too little rest – the body can't keep up with recovery and heart rate stays higher.
- Infection – resting heart rate often rises before the first symptoms of illness.
- Alcohol, caffeine and late meals – they raise night-time heart rate.
- Stress and lack of sleep – keep the nervous system on alert.
- Dehydration and heat – less fluid means the heart has to beat faster.
- Medical causes – anemia, an overactive thyroid, fever, some medications or rhythm disorders.
- Loss of fitness – after a longer break from exercise, resting heart rate naturally rises.
What to check
- The trend – track morning or night-time heart rate over several weeks, not individual days.
- TSH and fT4 – to rule out an overactive thyroid.
- Blood count and ferritin – anemia is a common cause of a faster pulse.
- CRP and blood pressure – inflammation and blood pressure complete the picture of heart and vessel health.
What helps
- Rest days – reduce training intensity after a demanding period.
- Regular sleep – at least 7 hours at a consistent time.
- Hydration and less alcohol – enough fluids and limiting alcohol show up quickly in the data.
- Low-intensity endurance training – lowers resting heart rate over time.
- Calming down – breathing exercises, walks in nature, less stress in the evening.
When to see a doctor
See a doctor if your resting heart rate is persistently above 100 beats per minute, irregular, or comes with chest pain, shortness of breath, fainting, dizziness, marked weight loss or sweating. Call emergency services for sudden severe symptoms.