The investigators are conducting a randomised-controlled trial comparing high ventilation breathwork with retention (HVBR) to a breathwork placebo (paced breathing at 15breaths/min with brief retentions). The metric of 15b/min aligns with guidance from the British Journal of Nursing, Royal College of Physicians and Johns Hopkins Medicine which state that the average, healthy rate should range from: 12-20, 12-18 and 12-16b/min, respectively. The main questions the study attempts to address are: Does HVBR lead to improved state and trait mental health and wellbeing in a general population adult sample?

The study will be conducted entirely online through the research platform Prolific, so participant data will be anonymous. The investigators will collect self-reports of mental health and wellbeing before and after the three-week breathwork period, in addition to a follow-up three weeks later. Pre-post intervention and follow-up questionnaires will be completed online via the survey platform Qualtrics which will be linked to Prolific. Data on self-reported adherence to, and credibility/expectancy of, the breathwork will also be collected, along with participants' experiences to gauge the safety and tolerability of the breathwork protocol.

Inclusion Criteria (self-assessed):

• Fluent in English and living in the UK
• Have access to headphones
• Comfortable with faster breathing and holding breath
• Willing to only practice breathwork in safe environment, lying down in soft area (i.e., bed, sofa, carpet/mat), and always away from water & hard ground
• Willing to only practice the breathwork away from large meals (i.e., before or 1hour after) and bedtime (i.e., at least 1 hour before if practicing in evening)

Exclusion Criteria (self-assessed):

• Hypotension or hypertension (low or high blood pressure)
• History of respiratory or cardiovascular/heart problems or disease
• History of fainting or syncope
• Epilepsy or seizures
• History of panic disorder or panic attacks
• Cerebral aneurysm
• Have had problems with prior breathwork sessions (i.e., fainting)
• Pregnancy, think one might be pregnant, trying to get pregnant, or are breastfeeding
• Any problems which affect one's ability to pace their breathing (i.e., active/chronic respiratory infection including blocked nose/cough/cold/fever, etc.), breathlessness, abnormally slow breathing (bradypnea), or abnormally fast breathing (tachypnoea)
• Any other physical/mental health conditions or current life events which impair or affect one's ability to engage in activities involving breath control
• Are taking any regular medication other than the contraceptive pill, including medications to reduce blood pressure (i.e., Ramipril or other ACE-inhibitors), beta blockers (i.e., Propranolol), antidepressants, anxiolytics or any other psychotropic medications

All participant data will be anonymous (only Prolific user IDs will be seen). No identifiable personal information will be collected. Participants will be able to check a box if they are happy for our research team at the University of Sussex to include the data again in future studies related to breathwork and meditation, as well as share with other research groups, if these have gained independent ethical approval, based on the strict confidentiality terms described in the participant info/consent form.

Indefinitely after the study has been completed.

Our research team at the University of Sussex will have access. The datasets used and/or analysed during the current study will be available from the principal investigator on reasonable request to other researchers working on breathwork and meditation.