Table 1.

Studies comparing carbohydrate oxidation rate during exercise at the same absolute intensity at sea level and high altitude

Study	Subjects	Exercise type, intensity and VO₂	%VO₂max	Fed or Fasted	Altitude	Duration before test	Cho ox, g/min	Cho ox, %
Lundby & Van Hall (2002)	6 ♂ + 2♀	CE, 154 W, 60 min VO₂ = 1.9 L/min (SL) VO₂ = 1.9 L/min (HA)	SL = 45 HA = 54	Fed 2 h before CE	4,100 m	10 min	SL = 2.0	SL = 74
Lundby & Van Hall (2002)	6 ♂ + 2♀	CE, 154 W, 60 min VO₂ = 1.9 L/min (SL) VO₂ = 1.9 L/min (HA)	SL = 45 HA = 54	Fed 2 h before CE	4,100 m	10 min	HA = 2.5^*	HA = 87^*
Peronnet et al., (2006)	5 ♂	CE. 169 W, 80 min VO₂ = 2.3 L/min (SL) VO₂ = 2.2 L/min (HA)	SL = 54% HA = 78%	Fed, 3 h before CE	4,300 m	15 min	SL = 2.0	SL = 75
Peronnet et al., (2006)	5 ♂	CE. 169 W, 80 min VO₂ = 2.3 L/min (SL) VO₂ = 2.2 L/min (HA)	SL = 54% HA = 78%	Fed, 3 h before CE	4,300 m	15 min	HA = 2.6^*	HA = 92^*
Young et al., (2018)^a	6 ♂	TMW, 1.6–1.7 m/sec VO₂ = 1.6 L/min (SL) VO₂ = 1.6 L/min (HA)	SL = 40% HA = 60%	Fasted	4,300 m	5–6 h	SL = 1.2	SL = 57
Young et al., (2018)^a	6 ♂		SL = 40% HA = 60%	Fasted	4,300 m	5–6 h	HA = 1.1	HA = 53
Young et al., (2018)^b	8 ♂	TMW, 1.6–1.8 m/sec VO₂ = 1.8 L/min (SL) VO₂ = 1.7 L/min (HA)	SL = 40% HA = 60%	Fed during TMW	4,300 m	5–6 h	SL = 1.7	SL = 78
Young et al., (2018)^b	8 ♂		SL = 40% HA = 60%	Fed during TMW	4,300 m	5–6 h	HA = 1.5	HA = 70

Studies measuring carbohydrate oxidation (Cho ox, g/min) and % total energy expenditure derived by Cho ox (Cho ox, %) during exercise (cycle, CE; treadmill walking, TMW) at sea level (SL) and during first 24-h at high altitude (HA). Superscripts a and b indicate different trials from same study. ^*different from SL (P < 0.05); ^†different from corresponding HA trial in that study (P < 0.05)