This study will look at whether a simple exercise called the isometric wall squat can help lower blood pressure in adults who have both hypertension and obstructive sleep apnoea treated with CPAP. Obstructive sleep apnoea is a condition in which breathing repeatedly stops or becomes shallow during sleep, and it is closely linked to high blood pressure. Although CPAP helps treat sleep apnoea, it usually lowers blood pressure only a little, so additional non-drug strategies may be useful.

The study will compare two situations in the same participants: one session of wall squat exercise and one non-exercise control session. Each participant will take part in both sessions, but the order will be random. This design helps the researchers compare blood pressure changes more fairly within the same person.

Participants will first attend a familiarization session, where the study procedures will be explained and the exercise intensity will be checked. After that, they will complete the two study sessions at home, during their usual CPAP treatment visits. The sessions will be separated by at least 48 hours and completed within one week. Both sessions will be scheduled at the same time of day to reduce the effect of normal daily changes in blood pressure.

The main result the researchers will measure is the average systolic blood pressure during the 12 hours after each session, using ambulatory blood pressure monitoring. This means blood pressure will be measured over time while the participant goes about normal daily activities. The researchers want to find out whether a single session of wall squat exercise produces a greater blood pressure reduction than simply resting without exercise.

This study may help improve understanding of whether isometric exercise can be a practical, low-cost, home-based option to support blood pressure control in people with hypertension and CPAP-treated obstructive sleep apnoea.