title: Acute Effects of Caffeine on Heart Rate Variability, Blood Pressure and Tidal Volume in Paraplegic and Tetraplegic Compared to Able-Bodied Individuals: A Randomized, Blinded Trial.
abstract: Caffeine increases sympathetic nerve activity in healthy individuals. Such modulation of nervous system activity can be tracked by assessing the heart rate variability. This study aimed to investigate the influence of caffeine on time- and frequency-domain heart rate variability parameters, blood pressure and tidal volume in paraplegic and tetraplegic compared to able-bodied participants. Heart rate variability was measured in supine and sitting position pre and post ingestion of either placebo or 6 mg caffeine in 12 able-bodied, 9 paraplegic and 7 tetraplegic participants in a placebo-controlled, randomized and double-blind study design. Metronomic breathing was applied (0.25 Hz) and tidal volume was recorded during heart rate variability assessment. Blood pressure, plasma caffeine and epinephrine concentrations were analyzed pre and post ingestion. Most parameters of heart rate variability did not significantly change post caffeine ingestion compared to placebo. Tidal volume significantly increased post caffeine ingestion in able-bodied (p = 0.021) and paraplegic (p = 0.036) but not in tetraplegic participants (p = 0.34). Systolic and diastolic blood pressure increased significantly post caffeine in able-bodied (systolic: p = 0.003; diastolic: p = 0.021) and tetraplegic (systolic: p = 0.043; diastolic: p = 0.042) but not in paraplegic participants (systolic: p = 0.09; diastolic: p = 0.33). Plasma caffeine concentrations were significantly increased post caffeine ingestion in all three groups of participants (p<0.05). Plasma epinephrine concentrations increased significantly in able-bodied (p = 0.002) and paraplegic (p = 0.032) but not in tetraplegic participants (p = 0.63). The influence of caffeine on the autonomic nervous system seems to depend on the level of lesion and the extent of the impairment. Therefore, tetraplegic participants may be less influenced by caffeine ingestion.
  
  
  
  ClinicalTrials.gov NCT02083328.
authors: Institute of Sports Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland.
authors: Joelle Leonie
authors: JL
authors: Flueck
authors: Institute of Human Movement Sciences and Sport, ETH Zurich, Switzerland.
authors: Fabienne
authors: F
authors: Schaufelberger
authors: Institute of Human Movement Sciences and Sport, ETH Zurich, Switzerland.
authors: Martina
authors: M
authors: Lienert
authors: Division of Cardiovascular Prevention, Rehabilitation and Sports Medicine, University Clinic for Cardiology, Inselspital, University Hospital and University of Bern, Bern, Switzerland.
authors: Daniela
authors: D
authors: Schäfer Olstad
authors: Division of Cardiovascular Prevention, Rehabilitation and Sports Medicine, University Clinic for Cardiology, Inselspital, University Hospital and University of Bern, Bern, Switzerland.
authors: Matthias
authors: M
authors: Wilhelm
authors: Institute of Sports Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland.
authors: Claudio
authors: C
authors: Perret
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects*; D001795:Blood Pressure Determination; D002110:Caffeine / Q000009:adverse effects* / Q000097:blood; D004311:Double-Blind Method; D004837:Epinephrine / Q000097:blood; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010264:Paraplegia / Q000378:metabolism / Q000503:physiopathology*; D011782:Quadriplegia / Q000378:metabolism / Q000503:physiopathology*; D012119:Respiration / Q000187:drug effects*; D013990:Tidal Volume / Q000187:drug effects; D055815:Young Adult
chemical_list: D002110:Caffeine; D004837:Epinephrine