The acylated (AG) and deacylated (DAG) versions of ghrelin, are known to influence appetite. Acute exercise has been demonstrated to alter ghrelin levels, but there is little information on how exercise intensity affects AG and DAG levels and how these levels affect appetite, and most of the evidence is confined to males.

      A study published in ‘Journal of Endocrine Society’ investigated the effect of exercise intensity and sex on ghrelin levels and appetite in untrained humans and included eight males (age: 43.1 ± 10.9 years; body mass index [BMI]: 22.2 ± 1.7 kg/m²; peak oxygen consumption [VO2peak]: 36.3 ± 6.4 mL/kg/min) and 6 females (age: 32.2 ± 11.1 years; BMI: 22.7 ± 1.0 kg/m²; VO2peak: 29.2 ± 4.0 mL/kg/min) who completed a maximal graded cycle ergometer lactate threshold (LT)/VO2peak test. These data were used to determine the exercise intensity on 3 subsequent randomized control or calorically matched cycle exercise bouts: (1) CON, no exercise; (2) MOD, the power output at LT; (3) HIGH, the power output associated with 75% of the difference between LT and VO2peak. Perception of appetite was analyzed using visual analog scales.

      The results revealed that females had higher levels of total ghrelin (TG) and DAG at baseline than males. Both groups exhibited reduced DAG levels in HIGH compared with MOD and CON (P < .0001-.004); however, only females had significantly reduced AG in HIGH (P < .0001).

      The study concluded that sex may influence this response, and high-intensity exercise may be better than moderate-intensity exercise at lowering ghrelin levels and altering appetite.