Author(s): WAINWRIGHT, B., 1,5. WAINWRIGHT, B., 1. SNAPE, D., 1. STAVROPOULOS-KALINOGLOU, A., 2. BURKE, S., 1,4. WOODS, D., 3. JACKSON, D., 1. O’HARA, J. , Institution: LEEDS BECKETT UNIVERSITY, Country: UNITED KINGDOM, Abstract-ID: 2302

INTRODUCTION:
Chemotherapy-induced anaemia is a side effect of chemotherapy that can affect red blood cell production and haemoglobin mass (Hbmass), reducing the oxygen-carrying capacity of blood. The low PO2 at high altitude reduces the diffusive gradient of oxygen between the lung and muscle, and therefore Hbmass plays a critical role in determining the physiological compensatory mechanisms, and ultimately the exercise capacity at altitude. The objective of this study was to investigate the physiological response to simulated high altitude of an experienced mountaineer following chemotherapy treatment. The outcomes were to be used to plan a suitable pre-expedition acclimatisation intervention before an oxygen-supported ascent of Mount Everest.
METHODS:
One female cancer patient (50 yrs), 8 months post-chemotherapy, with previous ascents to extreme altitude, completed 2 incremental submaximal tests: sea-level (SL) (Leeds, UK, 95 m), and at an equivalent of 5000 m (FiO2 10.8%, 986 mbar) (H) in a normobaric environmental chamber (Sporting Edge UK), 4-days apart. Treadmill speed at 3.0 km/h, with gradient increasing 2.5% every 3 minutes. The participant carried a rucksack weighing 10 kg throughout. Cardio-respiratory measures (Cortex Metalyser), pulse oximetry (Nellcor), muscle oxygenation (NIRS, Train.Red), RPE and Feeling Scale were measured. Hbmass and full blood count were measured 24 hours post the first test.
RESULTS:
In H, the cardio-respiratory system increased activity to deliver oxygen to meet the demands of the muscle’s contractile activity. At the highest common treadmill gradient (17.5%) there were a number of differences between H and SL: RPE +6.0 (16 vs 10), FS -6.0 (-1 vs 5), HR +43.6 (159 vs 115 b/min), Ve +12.3 (47.4 vs 35.0 l/min), Bf +2.7 (29.0 vs 26.3 br/min), VT +0.27 (1.63 vs 1.37 l), VO2 -2.6 (23.2 vs 25.7 ml/kg/min), SpO2 -52 (44 vs 96%), SmO2 -21.5 (60.0% vs 81.5%). Hbmass 442g (6.97 g/kg), RBC 4.29 10*12/L, Haematocrit 0.39, Hb 135 g/L. Of note, in H, SpO2 and Hbmass were much lower than expected.
CONCLUSION:
Despite the reduced oxygen-carrying capacity of the blood, the uptake and transport of oxygen to the muscles must have been sufficient to allow sustainable exercise - the participant did not report undue stress, with high but not maximal perceived exertion and a low but not minimal Feeling Scale scores. However, it is likely (but not tested due to safety reasons), that further increases in exercise intensity or altitude would have led to exercise cessation. The outcomes of this study suggest that measures of HBmass may be important in identifying chemotherapy-induced anaemia, despite normal Hb. For this participant, moderate intensity exercise was possible at very low SpO2 despite a low oxygen-carrying capacity of the blood. The results also suggest that post-chemotherapy, patients intending to travel to low oxygen environments should be mindful of its potential impact on exercise capacity.