Morning exercise affects the absorption of oral levothyroxine: a single center pilot study.

Morning exercise after levothyroxine ingestion resulted in decreased TSH levels in all participants.

• All patients had decreased TSH levels after the 6-week exercise programme
• The decrease in TSH levels was statistically significant (p < 0.001)
• This is described as 'the first study which demonstrates the significant positive effect of morning exercise on the absorption of LT4 tablets'

The exercise protocol consisted of a 30-minute walk at regular speed immediately after taking daily levothyroxine treatment.

• Patients were required to walk for 30 minutes with a regular speed right after taking their daily LT4 treatments
• Breakfast was delayed until the first hour after LT4 intake
• The programme duration was 6 weeks
• Patients had primary hypothyroidism and fulfilled specified inclusion criteria

A significant positive correlation was found between TSH percentage change and daily dose of levothyroxine per kilogram of body weight.

• As the daily dose of LT4 increases, the percentage decrease of TSH level becomes greater
• The correlation was between TSH percentage change and daily dose of LT4 per kg of body weight
• This finding suggests a dose-dependent relationship between LT4 dose and the exercise effect on absorption

The effect of exercise on oral levothyroxine absorption had not been previously reported prior to this study.

• Several factors influencing oral LT4 absorption have been previously described, but exercise had not been among them
• This is described as a single center pilot study
• The study is identified as the first to investigate the possible effect of morning exercise on LT4 tablet absorption