Although the primary organ of gas exchange is the lung, it has been recognized for some time that other organs have a potential role in gas exchange. There is emerging evidence that the gastrointestinal tract may have the capacity to act as an organ of gas exchange.

Several recent studies in both animals and humans have indicated that orally administered oxygenated nanobubbles is a safe intervention that can improve tissue oxygenation. Oxygen nanobubbles can reduce the hypoxia in tumours when injected, in conjunction with sonodynamic therapy. In mice, researchers have shown a reduction in tumour hypoxia and improved response to sonodynamic therapy occurs even when the oxygen nanobubbles are orally administered.

This will be an in vivo randomized, double-blinded, cross-over, placebo-controlled study consisting of rowers. By measuring the time taken by participants to complete a 2000m row after consuming an Oxygen nanobubbles drink, and a placebo drink, the investigators will evaluate the efficacy of the nanobubbles on the exercising ability of the participant.

Although the primary organ of gas exchange is the lung, it has been recognized for some time that other organs have a potential role in gas exchange. There is emerging evidence that the gastrointestinal tract may have the capacity to act as an organ of gas exchange. Several animal studies have demonstrated that oxygen (delivered as a gas and within enriched water) is capable of diffusing through the mucosa of the colon, peritoneum and stomach resulting in elevated oxygen tension in the splanchnic circulation (hepatic portal vein, arterial and venous mixed blood) and increased blood flow (portal venous blood flow). One MRI study has demonstrated that orally administered oxygen-supersaturated water causes a significant increase in the luminal oxygen concentration in both the oral cavity and the stomach, despite a low amount of oxygen added to the overall oxygen balance of the body.

Several recent studies in both animals and humans have indicated that orally administered oxygenated nanobubbles is a safe intervention that can improve tissue oxygenation. Oxygen nanobubbles can reduce the hypoxia in tumours when injected, in conjunction with sonodynamic therapy. In mice, researchers have shown a reduction in tumour hypoxia and improved response to sonodynamic therapy occurs even when the oxygen nanobubbles are orally administered. A study of male cyclists also showed that ingested oxygen nanobubbles led to an increased power output.

This will be an in vivo randomized, double-blinded, cross-over, placebo-controlled study consisting of rowers. By measuring the time taken by participants to complete a 2000m row after consuming an Oxygen nanobubbles drink, and a placebo drink, the efficacy of the nanobubbles on the exercising ability of the participant will be evaluated. This will be supplemented with a comparison of a pre-intervention and post-intervention validated Rate of Perceived Exertion (RPE) breathlessness questionnaire and measurement of blood lactate and glucose, blood gases, respiratory gas exchange and heart rate.

Inclusion Criteria:

• Participant is willing and able to give informed consent for participation in the research
• Participant is 18+ years of age
• Not currently taking any medications (except the contraceptive pill)
• The participant must be a competitive rower, with an estimated 2000m time of ≤6:30 minutes for males, and ≤ 8 minutes for females.
• The participant agrees to abstain from tobacco and nicotine products 24 hours before each visit.
• The participant agrees to abstain from alcohol 24 hours before each visit.
• The participant is, in the opinion of the investigator, healthy on the basis of a self-reported medical history, vital signs.
• The participant has no active disease process that could interfere with endpoints.
• Available for the duration of the study.
• The participant is not taking regular medications (including NSAIDs such as ibuprofen) that could interfere with endpoints measured and/or influence gastrointestinal permeability and led to gastrointestinal symptoms.
• The participant has not taken dietary/nutritional supplements in the preceding 2 weeks.
• The participant is not following a weight reducing diet.
• The participant is willing not to undertake strenuous or unaccustomed physical exercise for at least 24 hours prior to screening and study visits.

Exclusion Criteria:

• Participants with a history of smoking in the previous 30 days
• Participants that are allergic or intolerant towards: Liquorice, Lecithin derived from soya or sunflower, Citric acid, Glycerol
• Clinically significant cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, neurological, immunological, or haematological disease or abnormality, as determined by the self-reported health questionnaire.
• History of alcohol, narcotic, benzodiazepine, or other substance abuse or dependence within the 12 months preceding study visit 1.
• Currently participating in another study with an investigational or non-investigational drug or device, or has participated in another clinical study within the 2 months preceding study visit 1 (based on participant's self report).
• Any condition that, in the investigator's opinion, compromises the participant's ability to meet protocol requirements or to complete the study.
• Participant is pregnant and/or breastfeeding