Sub‐maximal aerobic exercise training reduces haematocrit and ameliorates symptoms in Andean highlanders with chronic mountain sickness

Abstract

Excessive erythrocytosis is the hallmark sign of chronic mountain sickness (CMS), a debilitating syndrome associated with neurological symptoms and increased cardiovascular risk. We have shown that unlike sedentary residents at the same altitude, trained individuals maintain haematocrit within sea-level range, and thus we hypothesise that aerobic exercise training (ET) might reduce excessive haematocrit and ameliorate CMS signs and symptoms. Eight highlander men (38 ± 12 years) with CMS (haematocrit: 70.6 ± 1.9%, CMS score: 8.8 ± 1.4) from Cerro de Pasco, Peru (4340 m) participated in the study. Baseline assessment included haematocrit, CMS score, pulse oximetry, maximal cardiopulmonary exercise testing and in-office plus 24 h ambulatory blood pressure (BP) monitoring. Blood samples were collected to assess cardiometabolic, erythropoietic, and haemolysis markers. ET consisted of pedalling exercise in a cycloergometer at 60% of VO 2 peak for 1 h/day, 4 days/week for 8 weeks, and participants were assessed at weeks 4 and 8. Haematocrit and CMS score decreased significantly by week 8 (to 65.6 ± 6.6%, and 3.5 ± 0.8, respectively, P < 0.05), while VO 2 peak and maximum workload increased with ET (33.8 ± 2.4 vs. 37.2 ± 2.0 ml/min/kg, P < 0.05; and 172.5 ± 9.4 vs. 210.0 ± 27.8 W, P < 0.01; respectively).Except for an increase in high-density lipoprotein cholesterol, other blood markers and BP showed no differences. Our results suggest that reduction of haematocrit and CMS symptoms results mainly from haemodilution due to plasma volume expansion rather than to haemolysis. In conclusion, we show that ET can effectively reduce haematocrit, ameliorate symptoms and improve aerobic capacity in CMS patients, suggesting that regular aerobic exercise might be used as a low-cost non-invasive and non-pharmacological management strategy.

Low‐ and moderate‐intensity aerobic exercise improves the physiological acclimatization of lowlanders on the Tibetan plateau

“…Our study showed that LI and MI exercises improve O 2 transport without erythrocytosis. Participants in the LI and MI groups experienced an increase in $$\dot{\mathrm{V}}$$O 2peak after the intervention, consistent with a previous study finding that exercise training in highlanders can successfully improve aerobic capacity and exercise workload (Macarlupu et al., 2021). Additionally, we found that LI exercise increased CO, as has been reported previously (Nystoriak & Bhatnagar, 2018).…”

Preserved peak exercise capacity in Andean highlanders with excessive erythrocytosis both before and after isovolumic hemodilution

“…A possible additional limitation to our study is the contribution of age to the variation in peak V̇ o 2 . Analysis of pooled data from our study and two different studies in male highlanders from Cerro de Pasco in the age range 24–64 yr ( 30 , 56 ) shows a weak but significant correlation between peak V̇ o 2 and age ( r = 0.33, P < 0.05, n = 43). Although we did not observe this association in our sample, possibly due the reduced number of participants, age was not an intrastudy determinant of peak V̇ o 2 neither in the non-EE nor the EE group both pre- or post-IVHD (either separate or combined), and thus can be considered as a uniform variable.…”