Three to 5 maximal breath-holds have been demonstrated to increase subsequent apnoea time by up to 20%, likely via bradycardia and increased haematocrit (Hct) and haemoglobin (Hb) (Baković et al. 2003;Richardson et al. 2005). These responses are consistent with the mammalian dive reflex (MDR) on facial immersion in cold water. As anecdotal evidence suggests longer apnoea times from breath-hold techniques (BHT) used by free divers, the aim of the present study was to investigate the apnoea duration and cardiorespiratory response to facial immersion following different BHT. Ten healthy males (34.5 ± 6.15 y(± SEM)) attended 5 randomised experimental visits where they were seated upright, underwent a 40 min BHT followed by a maximal breath hold challenge (MBH) with facial immersion, and a further 60 min of rest. On each visit, a finger plethysmograph and face mask (Human NIBP Nano, ADInstruments) measured continuously for mean arterial blood pressure (MABP), heart rate (HR), cardiac output (CO), total peripheral resistance (TPR), stroke volume (SV), and end tidal CO2(ETCO2) O2(ETO2), and an antecubital cannula for venous blood sampling of Hb and Hct every 20 min and immediately after MBH. The BHT consisted of a quiet rest control followed by facial immersion in water at 30°C (CON) or 10°C (MDR), or facial immersion in water at 30°C following 15×1 min breath-hold sets with separated by a reducing recovery time (2:50 min -10s for each set; TOL)), 15 sets of increasing duration (30s +10s for each set; BUILD) with a 1 min recovery time, and 23 sets of increasing duration (20s +10s) and recovery time (40s*9 sets, 50s*3 sets, 60s*11 sets; TV). MBH duration and cardiorespiratory values analysed using one- and two-way (group*time) ANOVAs, respectively. MDR lowered HR (P=0.032) and CO (P=0.056) during MBH compared to CON, increased Hb, but did not increase MBH duration. MBH duration was around 30% greater than CON in TOL (P=0.040), BUILD (P<0.001), and TV (P=0.001), despite similar HR responses. Hb and Hct during MBH was greater in BUILD vs. CON (P=0.027), whereas MABP was lower (P<0.001). TPR was greater than CON in TV and Hct was greater than CON in TOL. ETCO2was lower and ETO2was greater prior to MBH in TOL, BUILD, and TV compared to CON, whereas MDR had similar values to CON. Consistent with the MDR, facial immersion in cold water produces a marked bradycardia and cardiorespiratory response, but these do not appear to improve apnoea duration. Some of these responses are also seen with various BHT routinely used by free divers. However, the most robust responses associated with increased apnoea time across all three BHT protocols appeared to be decreases in ETCO2and increases in ETO2 prior to breath-hold, confirming that apnoea duration can be extended by manipulating blood gases, whilst suggesting that cardiac output and red blood cell mass are not obligatory.