The effects of sodium bicarbonate (NaHCO₃) ingestion on high intensity cycling capacity

Abstract

Ten healthy, non-cycling trained males (age: 21.2 ± 2.2 years, body mass: 75.9 ± 13.4 kg, height: 178 ± 6 cm, [Vdot]O_2PEAK: 46 ± 10 ml · kg⁻¹ · min⁻¹) performed a graded incremental exercise test, two familiarisation trials and six experimental trials. Experimental trials consisted of cycling to volitional exhaustion at 100%, 110% and 120% W_PEAK, 60 min after ingesting either 0.3 g · kg⁻¹ body mass sodium bicarbonate (NaHCO₃) or 0.1 g · kg⁻¹ body mass sodium chloride (placebo). NaHCO₃ ingestion increased cycling capacity by 17% at 100% W_PEAK (327 vs. 383 s; P = 0.02) although not at 110% W_PEAK (249 vs. 254 s; P = 0.66) or 120% W_PEAK (170 vs. 175 s; P = 0.60; placebo and NaHCO₃ respectively). Heart rate (P = 0.02), blood lactate (P = 0.001), pH (P < 0.001), [HCO₃ ⁻], (P < 0.001), and base excess (P < 0.001) were greater in all NaHCO₃ trials. NaHCO₃ attenuated localised ratings of perceived exertion (RPE_L) to a greater extent than placebo only at 100% W_PEAK (P < 0.02). Ratings of abdominal discomfort and gut fullness were mild but higher for NaHCO₃. NaHCO₃ ingestion significantly improves continuous constant load cycling at 100% W_PEAK due to, in part, attenuation of RPE_L.

Keywords:

• ergogenic aids
• alkalosis
• metabolic buffers
• pH
• RPE