We will recruit 16 individuals for each of the three groups (Young adults, older adults and individuals with type 2 diabetes). Participants will be recruited from a database of volunteers who have consented to being contacted for research studies which are held by the NIHR Exeter Clinical Research Facility. This is a double blind, placebo controlled crossover design study (nitrate rich beetroot juice vs a placebo, nitrate depleted beetroot juice). Three visits will be required for participants to complete this study.