Physiologic responses to exercise of irradiated and nonirradiated Shetland ponies: a five-year study.

This research study compares the physiological responses to exercise for two groups of Shetland ponies (one irradiated and the other non-irradiated) over a period of five years, starting when the ponies were three years old and five months after radiation exposure. Differences were noted in heart rates, respiratory rates, and rectal temperature responses during exercise and high-temperature conditions. The findings suggest that irradiated ponies generally displayed slower heart rate recovery post-exercise and exhibited higher respiratory rates and rectal temperatures when exercising in warmer environments.

Objectives of the Study

• The study aims to understand the physiological effects of gamma radiation on Shetland ponies, particularly in relation to exercise and high ambient temperatures.
• It focuses on the physiological differences between irradiated ponies and their non-irradiated counterparts over a period of five years.

Research Design and Methodology

• The Shetland ponies were exposed to 650 R (Roentgen) of Cobalt-60 gamma radiation when they were three years old.
• The researchers then measured the physiological responses (heart rate, respiratory rate, and rectal temperatures) to controlled exercise in both the irradiated and non-irradiated ponies at intervals over a five-year period.
• The study also accounted for the effects of high ambient temperatures to understand the effect of heat on the ponies’ physiology.

Key Findings

• Irradiated ponies generally had slower heart rates during recovery immediately after exercise, compared to non-irradiated ponies.
• They also demonstrated higher respiratory rates and rectal temperatures when exercising in an environment with a temperature of 29.5 degrees Celsius.
• Interestingly, exhaustive exercise did not increase these differences, which were already apparent with moderate exercise.
• The researchers observed that from a general viewpoint, the irradiated group performed work as efficiently as the non-irradiated group.

Conclusion

• Changes observed in the blood-cell concentrations of the irradiated ponies after exposure to radiation were similar to those observed in other large animal species under similar conditions.
• The time required for the count of various types of blood cells to return to their base line (pre-radiation) values varied between three months and three years.