Report

Spinal cord injury level influences acute plasma caffeine responses

Investigating the absorption and acute effects of caffeine at rest in individuals with no spinal cord injury (SCI), paraplegia (PARA), and tetraplegia (TETRA).

Lead academic:
Dr Terri Graham-Paulson
Additional academics:
Dr Thomas Paulson, Professor Vicky Tolfrey
Funder:
The Peter Harrison Foundation, Swiss Paraplegic Research Centre

Introduction:

Caffeine supplementation (3–6 mg·kg−1 body mass [BM]) can improve long and short-term endurance performance in able-bodied (AB) participants. However, there is limited research on the effects of caffeine on exercise performance in physically impaired populations, e.g., persons with a spinal cord injury (SCI). 

Caffeine absorption by impaired populations may be slower because of delayed gastrointestinal transit times and prolonged gastric emptying (GE). Understanding an individual's time to peak caffeine concentration has been shown to have little impact on prolonged AB endurance cycling performance. Whereas a beneficial effect of caffeine (4–6 mg·kg−1 in capsule form) on short-term wheelchair propulsion exercise has been previously reported.

Study aim: to explore the time course of caffeine absorption and its effects at rest in individuals with no spinal cord injury (SCI), paraplegia (PARA), and tetraplegia (TETRA). 

Methods:

  • Twenty-four healthy males (eight able-bodied [AB], eight PARA, and eight TETRA) consumed 3 mg·kg caffeine anhydrous (CAF) in a fasted state. Plasma caffeine [CAF], glucose, lactate, free fatty acid, and catecholamine concentrations were measured during a 150-min rest period.

Main findings:

  • Peak [CAF] was greater in TETRA (21.5 μM) compared with AB (12.2 μM) and PARA (15.1 μM), and mean peak [CAF] occurred at 70, 80, and 80 min, respectively.
  • The change in plasma catecholamine concentrations after CAF did not reach significance (P > 0.05); however, both adrenaline and noradrenaline concentrations were lowest in TETRA.
  • Significant increases in free fatty acid were seen over time (P < 0.0005), but there was no significant influence of SCI level.
  • Blood lactate concentration reduced over time (P = 0.022), whereas blood glucose concentration decreased modestly (P = 0.695), and no difference between groups was seen (P > 0.05).
  • The level of SCI influenced the caffeine absorption curve, and there was large interindividual variation within and between groups.
  • TETRA should trial low doses in training and PARA may consider consuming caffeine greater than 60 min before exercise performance. 

Reference

Graham-Paulson TS, Paulson TA, Perret C, Tolfrey K, Cordery P, Goosey-Tolfrey VL. Spinal Cord Injury Level Influences Acute Plasma Caffeine Responses. Med Sci Sports Exerc. 2017 Feb;49(2):363-370. DOI: 10.1249/MSS.0000000000001108 PMID: 27669443.