Sometimes called Fitness to Drive, health is an important factor in driving. In the long-term, any pre-existing or new medical condition which may affect your ability to drive safely must be reported to the Driver and Vehicle Licensing Agency (DVLA)
This is generally a conversation you should have with your doctor or specialist. A complete list of notifiable conditions is available on the gov.uk website
In the shorter term, minor illness or tiredness can affect your ability to drive safely, and it is up to you, as a responsible person, to decide for yourself if you are fit to drive or not.
Perhaps you have a headache? Could you delay your journey for an hour while you take some over-the-counter pain killers? If you have a cold and cannot give driving your full attention, could you work from home or lift-share?
Do you even need to drive? Would walking or public transport be a safer option for everybody?
If you are on any medication, read the information leaflet, or ask your doctor or pharmacist how it might affect your driving. Many medications state do not operate machinery…remember a car is a machine too!
And we cannot end a discussion on fitness to drive without mentioning recreational drugs, including alcohol. Recreational drugs are subject to a strict liability law, which essentially means zero tolerance. Alcohol has a more forgiving limit but any amount of alcohol in your system will have a detrimental effect on your driving.