The HLTH Journal·Heart Health
High resting heart rate: causes and when to worry
Stress, a bad night, a coffee or a cold will all do it. A few other things are worth a conversation with your doctor.
HLTH Science Team· May 2026 · 5 min read
You checked your resting heart rate and it looks high. Should you worry? Sometimes no, sometimes yes. A high resting heart rate can come from many things. Here is what is normal, what is not, and when to call your doctor.
Key takeaways
- Above 100 bpm at rest is called tachycardia; 60 to 100 is the normal adult range.
- One elevated reading after a bad night or a stressful morning is rarely meaningful.
- Most causes are lifestyle-related and reversible; a few are treatable conditions worth diagnosing.
- Never stop a medication over a wearable reading. Ask your doctor about an alternative.
What counts as high?
A normal resting heart rate for adults sits between 60 and 100 beats per minute. Below 60 is common in people who exercise regularly. Above 100 at rest is called tachycardia. A single elevated reading after a poor night’s sleep or a stressful morning is rarely meaningful on its own. What matters is your average across several days, measured when you are genuinely at rest.
What can cause it
Most causes are temporary and self-resolving. Stress or anxiety raises heart rate quickly through adrenaline, and it drops once the stressor passes. Poor sleep can push resting heart rate up by 5 to 10 beats the following day. Alcohol disrupts sleep quality and elevates both overnight and morning readings. Caffeine stimulates the nervous system, with the effect fading within a few hours. Dehydration lowers blood volume, so the heart beats faster to maintain circulation. And illness or fever raises heart rate roughly 10 beats per degree of elevated body temperature. A second group is worth discussing with your doctor. Deconditioning, meaning a sedentary period, raises baseline heart rate over weeks, and it responds well to gradual exercise. Certain medications, including stimulants, some decongestants and certain asthma medications, raise resting heart rate as a side effect. An overactive thyroid speeds up the body’s processes including heart rate, and is treatable once diagnosed. Anaemia means a reduced red blood cell count, so the heart works harder to deliver oxygen, and a blood test can confirm it. Persistent anxiety keeps the nervous system in a low-level alert state, which elevates baseline heart rate over time. The important thing to hold onto is that most of these causes are either self-resolving or treatable. A high resting heart rate is a signal worth paying attention to, not something to panic about.
What you can do
If your resting heart rate looks elevated and there is no obvious explanation such as illness or a heavy week, the most useful first step is checking your lifestyle basics. Sleep, hydration, alcohol intake and stress levels account for the majority of temporary elevations. Regular aerobic exercise is the most reliable long-term way to lower resting heart rate. Even moderate activity, such as 30 minutes of brisk walking most days, produces a measurable reduction over weeks: the heart becomes more efficient and requires fewer beats to do the same work. If you suspect a medication is the cause, do not stop taking it without speaking to your doctor first. There may be an alternative that does not carry the same effect.
When to see a doctor
Contact your doctor if your resting heart rate is consistently above 100 beats per minute when measured at rest, away from exercise, caffeine and stress. Also seek advice if a high reading comes with any of the following: chest pain or tightness, dizziness or lightheadedness, shortness of breath at rest, or a feeling that your heart is pounding or fluttering. These combinations are not necessarily serious, but they are worth investigating rather than monitoring from home.
