Methods
Patients
Consecutive patients with positive HUTT were invited to participate in the study. All participants were aged >16 and had had at least two syncopal episodes in the 
previous 12 months and a positive HUTT. A positive HUTT was defined as a reduction in blood pressure associated with syncope. Exclusion criteria included the following: (i) inability to provide informed consent; (ii) physical or mental inability to perform HOT as determined by the investigators; and (iii) pregnancy.
Interventions
The local research ethics committee approved the study and written informed consent was obtained from all participants. All patients received normal clinical care in accordance with ESC guidelines for VVS. Subjects were divided into two cohorts: those aged >65 years (O65) and those aged <65 years (U65). The O65 group was randomised to receive either active HOT (O65+) or sham training (O65−). The U65 cohort were all actively trained and acted as an additional control group. Randomisation was performed by an independent clinician using computer-generated random numbers. Active or sham training was taught to the participant during a one-to-one training session. A written crib sheet of the training technique and regime was also provided. Participants and their clinicians not involved in the trial were blinded to the treatment group. Training was undertaken for a total of 3 months before a repeat HUTT was performed (Figure 1).
Active HOT
Participants in the U65 and O65+ groups were asked to stand with their backs against a wall supported by their head and shoulders and to move their feet 20 cm from the base of the wall. They were asked to hold this position for 30 minutes or until pre-syncopal symptoms occurred. Participants were warned to prepare the training area so that a prone position could be achieved quickly if symptoms occurred suddenly.
Sham Training
Participants in the O65− group were asked to stand with their backs against a wall supported by their head and shoulders but move their feet just 5 cm from the base of the wall. They were asked to hold this position for 5 minutes or until pre-syncopal symptoms occurred. As with the active group, participants were warned to prepare the training area so that a prone position could be achieved quickly if symptoms occurred suddenly.