Carbohydrates are an important source of energy for physical activity. When you don’t eat enough carbohydrates, they are stored in the muscles and liver, depleting glycogen. This impairs endurance and causes low blood sugar. Carbohydrates are an essential nutrient for athletes who engage in sustained physical activity.
Therefore, athletes need to consume more carbohydrates than the average person. For example, the Union of European Football Associations (UEFA) recommends consuming six to eight grams of carbohydrates per kilogram of body weight per day during when players are playing matches frequently. When converted to just rice, this would amount to nine to ten bowls for a 70-kg athlete.

Hiromatsu says she wants to explore the reasons for individual differences in carbohydrate intake and to create more comfortable and stress-free nutritional plans for athletes. Her first experiment was to determine how blood glucose levels during and after exercise varied depending on carbohydrate intake.

According to Hiromatsu, the results showed no significant differences in glucose concentration dynamics between the high-carbohydrate and moderate-carbohydrate diets during exercise and after exercise, including while asleep. This demonstrated that blood glucose levels can be maintained without a high-carbohydrate diet.

To conduct this study, Hiromatsu had to make strict adjustments to the diet served to the subjects, which was more difficult to prepare and execute than she expected.
To further advance her research, she plans to focus on glycogen in the liver, which is involved in blood sugar regulation and the capacity for sustained exercise. She is planning to conduct experiments with top-level endurance athletes, with the goal of generating meaningful research results for athletes competing at a higher level.

Hiromatsu is pursuing her studies in the doctoral program while still working as a registered dietitian. Looking back, she says her decision to seek a doctoral degree stems from her own experiences as a competitor as well as her undergraduate studies in the College of Sport and Health Science.

While she was enrolled in the College of Sport and Health Science, Hiromatsu applied what she learned in class about training science to devise athlete-centered practice regimens for the lacrosse team that she was a member of. This provided her with first-hand experience of how science and actual play on the field are linked, and she found it enjoyable to tackle both her desire to learn more theory and implement practical applications.

When she was studying for her registered dietitian certificate, Hiromatsu worked part-time as a cook in the cafeterias of professional baseball and basketball teams. After graduating from university and earning her certificate, she has been involved in food and sports in various ways, including devising meal menus. Later, Hiromatsu went on to provide nutritional support to soccer and basketball players, track and field athletes, and triathletes, as well as J-League youth teams, and she enjoyed a fulfilling career as a professional providing support to the players in the field. However, there were moments when she felt frustrated by the amount of knowledge she gained in the course of her work. She recounts:

Taking the initiative and aiming to make this wish a reality, Hiromatsu decided to enroll in a two-year online course for professionals offered under the auspices of the International Olympic Committee (IOC). She completed a large number of tests and reports in English and earned the IOC Diploma in Sports Nutrition. In the process of furthering her studies, she became interested in learning about more advanced data analysis methods and findings in sports science research. After consulting with a mentor from her university days, Hiromatsu took advantage of the entrance examination system of the Graduate School of Sport and Health Science and chose to pursue in-depth research in the doctoral program without having to first enroll in a master's program. She now spends her days studying and researching cutting-edge sport science while striking a balance with her work.

While Hiromatsu struggles to divide her time between research and work, she says that the balancing act has actually had a positive impact on both. She explains:

One of the next steps that Hiromatsu plans to take is to set up her own company.

Hiromatsu says she would also like to continue her academic endeavors by analyzing data from the athletes she supports and leaving a record in the form of an article. Her genuine desire to contribute to those who are truly committed to sports will continue to be the driving force behind her further learning.