Interval in Angular Service Forces DOM Update

I have the following Angular service defined in my project...

@Injectable({ providedIn: 'root' })
export class NodeService extends WebService {

  private intervalId: number | undefined;

  public start(frequency: number = 1000): void {
    if (this.intervalId === undefined) {
      this.intervalId = window.setInterval(() => { ... }, frequency);
    }
  }
}

When start is executed, it forces a DOM update every (frequency) milliseconds, even though the body of the setInterval function is empty.

Any ideas why?