Data from activity levels, food intake, weight, blood pressure etc if correctly recorded can give you data.
The accuracy is not all that critical and the sources of inaccuracy or error are known and expectations are realistic. So for example it is important that your weighing scales record your weight consistently (2 or 3 readings are quite close) but it does not mater if they are not as accurate as a laboratory scale.
The reason for this is we are interested in changes over time rather than the actual weight itself.
Provided the information you gather is consistent and reliably gathered there is no reason it could not be used to have a say in your own health care. Self monitoring is starting to be seen as the way forward.
Some doctors are more open to this than others and they will always verify a patient with their own measurements but they cannot monitor your blood pressure every morning – that is something you COULD do.
What every doctor should be encouraged by is people taking more responsibility for their own health and wellbeing so that doctors can focus on illness potentially with many fewer pressures on the system if the average patient were eating a more healthy nutritious diet and doing more exercise.
- Why Do I Need Repeat Hypertension Tests? (everydayhealth.com)
- Whose Health Is It Anyway? (themarmotinmyhead.com)
- Lower Blood Pressure By Keeping An Eye On It: Self-Monitoring To Reduced Hypertension (medicaldaily.com)
- Am I Really Getting Older Like Everyone Else Is? (retiredsyd.typepad.com)