Like anyone, a person with diabetes can have blood pressure that is lower than usual. The systolic blood pressure may be lower than 100 mmHg without blood pressure medication or any other obvious reason. It is not dangerous, as long as it does not cause any symptoms. If you experience vertigo or dizziness when you stand up to get out of bed, for example, you may have to sit down for a moment and wait for the pressure to stabilise.
Long-term diabetes may affect the autonomic nervous system regulating your blood pressure and heartbeat. Potential symptoms of nerve damage include a fast heart rate, low blood pressure and a drop in blood pressure when you stand up.
In the elderly, low blood pressure may be caused by arterial stiffness or cardiac failure. The effectiveness of blood pressure medication may be increased by weight loss and ageing. Some medicines other than blood pressure medication may also result in your blood pressure dropping too low.
If blood pressure is below 120–130/60–70 mmHg on person with blood pressure medication for a prolonged period of time – especially in the case of the elderly – it may be necessary to reduce the dose of the blood pressure medication. You should discuss the matter with a nurse or doctor in your treatment centre.