TABLE 3.

Thermoregulatory (basal, final and delta core body temperature) and performance outcomes for included studies investigating the effects of menstrual cycle phase on performance in hot conditions (k=6).

Study	Participant characteristics	Basal Tcore (°C)	Basal Tsk (°C)	Final Tcore (°C)	Delta Tcore (°C)	Performance test	Performance outcome
Hashimoto et al. (2014)	$\dot{\mathrm{V}}$ O2max 39.5 ±5.3 mL/kg/min. Physically active (n=2); not physically active (n=4)	Elevated in L vs. F (P<0.05)	Not reported	Elevated in L vs. F (P<0.05)	Not reported	90-min cycling (50% V̇O2peak) followed by TT	NS
Lei 2017	$\dot{\mathrm{V}}$ O2max 55 ±9 mL/kg/min. Trained cyclists/triathletes (n=10)	0.21 ±0.14 °C higher in ML vs. EF (P<0.05)	NS	0.23 ±0.28 °C higher in ML vs. EF in hot humid (P<0.05) no difference in hot dry	Elevated in EF (1.40 ±0.18) vs. ML (1.23 ±0.27; P<0.05)	30-min cycling TT	NS
Wright 2002*	$\dot{\mathrm{V}}$ O2peak 51 ±1.9 mL/kg/min. Trained runners	Elevated in L (37.7) vs. F (37.42 ±0.28; P<0.05)	Not reported	NS	Elevated in F vs. L (P<0.05)	30-min running TT	NS
Zheng et al. (2021)	$\dot{\mathrm{V}}$ O2max 46.4 ±7.1 mL/kg/min	0.28 ±0.25 °C higher in ML vs. EF (P<0.05)	NS	NS	NS	20-min fixed-intensity cycling followed by 30-min TT	NS
Janse de Jonge 2012	$\dot{\mathrm{V}}$ O2max 40.0 ±6.9 mL/kg/min Recreationally active.	Elevated in ML (37.2 ±0.3) vs. EF (37.0 ±0.2; P<0.05)	NS	NS	Rest to 45-min was 19% higher in ML (P<0.05)	60-min fixed-intensity cycling (60% $\dot{\mathrm{V}}$ O2max), followed TTE	TTE was 5.7% longer in EF than during ML (P<0.05)
Tenaglia 1999	$\dot{\mathrm{V}}$ O2max 44.8 ±2.6 mL/kg/min. Recreationally active.	Elevated in ML (37.31 ±0.08) vs. EF (37.09 ±0.08; P<0.05)	Elevated in ML (33.4 ±0.16) vs. EF (32.91 ±0.20; P<0.05)	NS	Elevated in EF vs. ML (P<0.05)	15-min walking, followed by 15-min seated rest until exhaustion	TTE was longer in EF (128.1 ±13.4 min) vs. ML (107.4 ±8.6 min; P<0.05)

Abbreviations: L, luteal; F, follicular; EF, early follicular; ML, mid luteal; T_core, core body temperature; T_sk, skin temperature; $\dot{\mathrm{V}}$ O_2max, maximal oxygen consumption; TTE, time to exhaustion; TT, time trial; NS, no significant difference between the menstrual cycle phases (P>0.05); mean ±SD. Delta T_core, difference between final and basal T_core. * indicates the study used a mixed cohort of naturally menstruating and OCP users.