|Sleeping on your side helps reduce apnea events. Image: Getty|
Obstructive sleep apnea (OSA) is a common yet serious disorder in which obstruction of the throat (upper airway) causes breathing to repeatedly stop and start, resulting in fragmented sleep, sleep deprivation, daytime tiredness and leaving OSA patients liable to a number of health risks.
Curiously, although obesity is the strongest risk factor for developing OSA, weight loss – while it can improve the severity of OSA – rarely cures it.
A study by Monash University and Alfred Hospital researchers published in 2012 that looked at morbidly obese patients with OSA who lost weight –– either medically through diet or bariatric (lap-band) surgery – confirmed this and left the researchers asking what else they could do to help patients for whom weight loss didn’t work.
A second study, published last month in the journal ‘Sleep’, provided an answer and pointed to an easy treatment option.
OSA can be a contributing factor to heart disease, stroke, hypertension and motor vehicle accidents. Studies have shown that people with untreated OSA underperform during the day. Moreover, the snoring associated with OSA often has adverse effects on those who live with OSA patients.
Recognising that the supine position (lying on the back) was a key factor exacerbating the severity of OSA in many patients, the researchers decided to test the effects of weight loss and body positioning during sleep.
Obese patients who had undergone weight loss were recruited from hospitals across Melbourne and tested sleeping in the supine and non-supine (lateral or side) positions using the apnea/hypopnea index (AHI). The AHI indicates the severity of sleep apnea determined by the number of apnea events (pauses in breathing) per hour of sleep and decrease in blood oxygenation.
The results demonstrated that the beneficial effect of weight loss was greater in patients who slept laterally compared to those who slept in the supine position. Importantly, 22% of patients who had undergone weight loss had their OSA normalised simply by preventing them from sleeping on their back.
“For the first time, we’ve been able to show that weight loss makes sleep apnea more positional,” said Professor of Medicine at Monash University Matthew Naughton, who was instrumental in designing and setting up the study.
“This gives validity to positional therapy, in other words, treatments that keep patients sleeping on their sides, which we’ve been using for many years,” Professor Naughton said.
The study was a collaboration between Monash University, Monash Medical Centre, The Alfred and the Baker Institute. First author was Dr Simon Joosten; Professor John Dixon from the Baker Institute and Monash University’s Dr Garun Hamilton jointly supervised the study.
Joosten SA, Khoo JK, Edwards BA, Landry SA, Naughton MT, Dixon JB, Hamilton GS. Improvement in Obstructive Sleep Apnea With Weight Loss is Dependent on Body Position During Sleep. Sleep. 2017 May 1;40(5). doi: 10.1093/sleep/zsx047.
Dixon JB, Schachter LM, O'Brien PE, Jones K, Grima M, Lambert G, Brown W, Bailey M, Naughton MT. Surgical vs conventional therapy for weight loss treatment of obstructive sleep apnea: a randomized controlled trial. JAMA. 2012 Sep 19;308(11):1142-9.