Q&A #66 - Whoop and Halo Sport - the next big things or riding the hype wave?  What is the evidence supporting the Whoop strap, that measures heart rate, heart rate variability (HRV) and tracks sleep?  Is continuous HRV-measurement overnight better than a standardised morning measurement?  Is there any validation for the accuracy of Whoop's measurements? What is the evidence supporting the Halo Sport neurostimulator, that uses transcranial direct current stimulation (tDCS) to supposedly improve athletic performance?  Issues with the marketing of both the Whoop and Halo Sport devices   LINKS AND RESOURCES: That Triathlon Show website  Coaching Training Plans Electrolyte beverage consumption alters electrically induced cramping threshold New lab-based evidence suggests electrolyte intake can help reduce cramps - Precision Hydration blog HRV-article by Marco Altini Is Brain Stimulation the Next Big Thing? - Alex Hutchinson The Ergogenic Effects of Transcranial Direct Current Stimulation on Exercise Performance Effect of transcranial direct current stimulation on exercise performance: A systematic review and meta-analysis. The effects of transcranial direct current stimulation on objective and subjective indexes of exercise performance: A systematic review and meta-analysis.     SPONSORS: ROKA - The finest triathlon wetsuits, apparel, equipment, and performance eyewear on the planet. Trusted by Javier Gómez, Gwen Jorgensen, Flora Duffy, Mario Mola, Lucy Charles and others. Get 20% off your entire order with the discount code TTS20.   Precision Hydration - One-size doesn't fit all when it comes to hydration. Take Precision Hydration's FREE sweat test and learn how you should hydrate. Use the discount code THATTRIATHLONSHOW and get your first box for free.   RATE AND REVIEW: If you enjoy the show, please help me out by subscribing, rating and reviewing.    CONTACT: Want to send feedback, questions or just chat? Email me at mikael@scientifictriathlon.com or connect on Instagram, Facebook, or Twitter.