Circulating venous bubbles in recreational diving: Relationships with age,weight, maximal oxygen uptake and body fat percentage

Decompression sickness (DCS) is recognized as a multifactorial phenomenon d epending on several individual factors, such as age, adiposity, and level o f fitness. The detection of circulating venous bubbles is considered asa us eful index for the safety of a decompression, because of the relationship b etween bubbles and DCS probability. The aim of this work was to study the e ffects of individual variables which can be assessed non invasively, on the grades of bubbles detected 60 min, after diving by means of Doppler monito ring, in a sample of 40 male recreational scuba divers. The variables inves tigated were: age, weight, maximal oxygen uptake ((V) over dot O(2)max) and percentage of body Fat (%BF). Bubble signals were graded according to the code of Spencer. The relationships between the bubble grades (BG) and the v ariables investigated were studied using two methods: the differences betwe en the average values of each variable at each BG were analyzed by the Sche ffe test. Then we performed the non-parametric Spearman correlation analysi s. Significant differences (P < 0.05) were found (Scheffe test) between ave rage values of the variables at grade 0 and 3 (age: P = 0.0323; weight: P = 0.0420; (V) over dot O(2)max: P = 0.0484), except: for %BF (P = 0.1697). R elationships with P < 0.01 were found (Spearman correlation) between BG and the variables: age: p = 0.486, P = 0.0024: weight: p = 0.463, P = 0.0039; (V) over dot O(2)max: p = -0.481, P = 0.0027; except for %BF: p = 0.362. P = 0.0237. This work showed that bubble production after hyperbaric exposure s depends on several idividual factors. The effects of age, weight and (V) over dot O(2)max are more significant than the effect of %BF, We concluded that to take into account such variables in decompression tables and diving computer programs should allow to adapt the decompression procedures to in dividual risk factors and reduce the DCS probability.