Seasonal changes of physical performance and adaptation process in laboratory rats following light desynchronosis modeling

BACKGROUND: Over the past five years, new data from both animal studies and epidemiological observations have provided additional evidence of the adverse effects of light desynchronosis on the body. Disruption of rhythmic organization inevitably leads to destabilization of homeostasis and a decline in the body’s adaptive capacity, potentially resulting in pathological conditions.

AIM: To investigate the seasonal changes of physical performance and the adaptation process in laboratory rats subjected to physical exercise following light desynchronosis modeling, and to assess serum lactate levels under these conditions.

METHODS: The study was conducted on 240 outbred adult male Wistar rats during the autumn–winter and spring–summer periods. Experimental desynchronosis was modeled by exposing the animals to either continuous bright artificial light (150 lx) or complete darkness (2–3 lx) for 10 days. To assess seasonal changes of performance, a forced swim test to exhaustion was used, administered once daily at the same time each day for five consecutive days. Serum lactate concentration was determined using a standard reagent kit.

RESULTS: A relationship was identified between physical performance and blood lactate levels in laboratory rats: higher performance was associated with lower lactate levels. The introduction of light desynchronosis, combined with the swimming test, influenced the changes of lactate concentration in specific ways.

CONCLUSION: The rhythmic pattern of seasonal changes in performance and serum lactate levels following light desynchronosis modeling indicates strain on the organism’s adaptive-compensatory mechanisms and disruptions in metabolic processes.