He added: “By planning ahead, particularly around managing medications and choosing the right service, people can make a real difference.”
A Secamb spokesperson urged people to look out for elderly relatives or neighbours, particularly regarding falls.
It also urged residents to use the 111 service when an ambulance was not required, or for advice on which service to use.
Following the Easter weekend, resident doctors from the British Medical Association are set to walk out from 07:00 BST on 7 April to 07:00 on 13 April.
Prof Andrew Rhodes, joint chief medical officer for NHS Sussex and Surrey Heartlands, said: “The NHS has well-established plans in place to ensure that essential services continue during industrial action, but we are likely to see increased pressure across our services.
“With illnesses such as norovirus currently circulating, it is especially important that people make use of the right service at the right time so they can get the help they need.”
Patients should also continue to attend appointments unless contacted directly by the NHS, a spokesperson said.