Getting out of bed and the world spins. Your heart races in the supermarket line. You need to sit down in the shower. And at the cardiologist, everything looks normal.
When the problem is not in the heart but in the system that commands it, conventional tests cannot see it. That system is the autonomic nervous system — and its dysregulation has a name: dysautonomia.
What the autonomic nervous system does
It controls everything that works without your thinking: heart rate, blood pressure, digestion, temperature, sweating. When you stand up, it adjusts circulation within seconds to keep blood reaching your brain.
In dysautonomia, that adjustment fails. Gravity pulls blood downward, the brain gets less perfusion, and the body compensates however it can — usually by speeding up the heart.
POTS: the most common form in young people
Postural Orthostatic Tachycardia Syndrome (POTS) is defined by a sustained increase of 30 or more beats per minute (40 in adolescents) upon standing, without a significant drop in blood pressure, accompanied by symptoms such as:
- Dizziness, darkened vision, feeling of imminent fainting
- Palpitations and tremors
- Disproportionate fatigue
- Brain fog
- Heat and exercise intolerance
- Worsening after hot showers and large meals
The connection few investigate
POTS rarely comes alone. The most described associations in the literature:
- Hypermobile EDS: lax connective tissue in vessels favors blood pooling in the legs
- MCAS: mast cell mediators cause vasodilation and worsen orthostatic symptoms
- Long COVID: infection can trigger or unmask dysautonomia
That is why treating "just the tachycardia" with a beta-blocker, without investigating the full picture, so often fails.
How the investigation is done
- Detailed history: in which position symptoms appear, what worsens, what relieves
- Standardized orthostatic measurement: heart rate and blood pressure lying and standing, at defined times
- Tilt table test when indicated
- Active search for comorbidities: hypermobility, mast cell symptoms, sleep quality
A data point you can bring to your appointment
Measure your heart rate lying down after 10 minutes of rest. Then stand still and measure at 2, 5 and 10 minutes. Write down the values and symptoms. This simple series of numbers can shorten the path to diagnosis by months.
A symptom without explanation is not a symptom without cause. It is a symptom without adequate investigation — yet.