Table II.

Categorisation of specific health consequences

Category	Inclusion summary
Reproductive health	Fertility, menstruation, impotence
Immunity	Resistance to illness, getting/becoming sick, fever
Vitality	Energy, fitness, weakness, sleep, metabolism
Iron	Iron levels, anaemia, supplement use
Blood loss	Losing too much blood or inability to replenish blood supply
Infectious disease	HIV, AIDS, malaria etc.
Health risk/protective factors	Blood pressure, development of cancer, cardiac arrest, diabetes etc
Physical appearance	Weight gain/loss, acne
Improving blood	Filtering blood, reducing thickness, replenishing/purifying blood (removing old), increasing circulation
Headache	Headaches, migraines
Death	Dying, accelerated ageing/reduced lifespan
Adverse events: vasovagal reactions	Fainting, dizziness, vertigo, nausea/ feeling sick/being sick, blurred vision, extreme changes in body temperature
Adverse events: other physical	Bruising, nerve damage, tingling, convulsions, muscle spasms, allergic reactions, and other specific injuries
Adverse events: non-specific	General mention of adverse events, feeling unwell, combination of vasovagal and other physical adverse events

Note: there were two exceptions to weakness being coded as vitality 1) when weakness in relation to anaemia, this was coded as iron; and 2) when weakness was raised in conjunction with other vasovagal reactions this was coded as adverse events: vasovagal reactions.