The overall aim of this study is to determine if face masks that can warm and humidify air can improve overall asthma control and markers of airway health during exercise in cold dry environments. We will investigate the potential protective benefits of the face masks against exercise induced asthma during 1) a "one-off" bout of exercise in a cold dry environment and 2) over the course of a four week period, exercising three times per week in a cold dry environment.

Physical activity is recognised as a trigger for individuals with asthma, however regular physical activity is considered to be important in the overall management of the condition. There is clear evidence that demonstrates if individuals with asthma engage with regular physical activity they will improve their physical fitness and breathing control, whilst at the same time experiencing reductions in asthma severity, symptoms, and medication use. In addition undertaking regular exercise reduces the risk of developing other diseases such as heart disease or type 2 diabetes. Despite the clear health benefits of engaging in regular physical activity there is evidence that some people with asthma avoid physical activity due to shortness of breath, worsening asthma symptoms during physical activity or fear of experiencing such symptoms.

Physical activity in cold dry environments exacerbates symptoms for many individuals with asthma resulting in greater avoidance of physical activity during the winter months. The increased risk of asthma from exercising in cold environments has led to Asthma UK advising susceptible individuals to avoid exercise outside in cold environments (http://www.asthma.org.uk/advice-exercise). This places obvious constraints and limitations on individuals with asthma for whom the aim of optimum treatment is to allow them to follow a "normal" lifestyle. Indeed, exposure to cold air on exertion is relevant to a significant proportion of individuals with asthma who engage with outdoor physical activity as part of their daily routine; e.g. cycle-commuting to work, outdoor construction workers.

A mask that is able to warm and humidify the air during exercise may provide a solution for asthmatic individuals susceptible to cold dry environments. There are a limited number of small studies that provide tentative evidence suggesting masks which warm and humidify air can protect against reductions in lung function during and following physical activity. However, it is unknown whether the use of these masks provides protection against the mechanisms that drive asthmatic symptoms. It is also unclear whether using the masks over a prolonged period of time significantly reduces asthma severity, inhaler use, or presence of symptoms.

The overall aim of this study is to determine if face masks that can warm and humidify air can improve overall asthma control and markers of airway health during exercise in cold dry environments. We will investigate the potential protective benefits of the face masks against exercise induced asthma during 1) a "one-off" bout of exercise in a cold dry environment and 2) over the course of a four week period, exercising three times per week in a cold dry environme

Inclusion Criteria:

• Ability to consent to the research
• Prior clinician based diagnosis of asthma
• Males and females
• 18 - 45 years
• Engage in regular exercise (at least twice weekly)
• Normal resting Forced Expiratory Volume in One Second (FEV1); defined as greater than 80% of predicted value.

Exclusion Criteria:

• Chest infection within the past 4 weeks, or any other illness within the past 2 weeks

• Fall in FEV1 >50% from baseline following exercise challenge (see protocol)

• Baseline FEV1 of < 80% of predicted

• Cardiovascular conditions:

  • Coronary Artery Disease
  • High Blood Pressure
  • Heart Failure
  • Diagnosed Abnormality of Heart Rhythm

• Metabolic diseases:

  • Type 1 diabetes
  • Type 2 diabetes
  • Pre-diabetes

• Daily use of oral corticosteroids

• Hospitalisation due to asthma in the six months prior to study commencement

• Injury or conditions that limit mobility

• Pregnancy

Heat Exchange Mask SHAM Mask