Fasting during Ramadan is for those who have attained puberty.
Islam does not require young children to fast, although many parents train them gradually over the years to enable them to fulfil this obligation by puberty, said Dr Sueziani Zainudin, a consultant endocrinologist at Sengkang Health's department of general medicine.
Parents will need to tailor the training to suit the child, as it depends on the child's readiness, maturity level, tolerance and ability to express his needs, she said.
"Ideally, fasting should be performed under adult supervision. Parents should ensure that the child is not unwell and does not engage in high-intensity physical activity, which could make fasting risky."
Such training should be done gradually, she said.
Studies have suggested that fasting affects a person's performance because it disturbs sleep patterns, food and fluid intake, as well as circadian rhythms, she said.
Thus, parents should ensure that the child remains active and alert while fasting.
If the child shows signs of dehydration, such as lethargy, dry mouth and decreased urine output, fasting should be terminated.
The child will need to be fed and, if necessary, receive medical attention, she said.
Parents whose child has health conditions but who wishes to fast should discuss it with a paediatrician, she added.